The Elbow and Its Disorders E-Book
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Description

A must-have resource for any orthopaedic library, the latest edition of this technique-focused guide to the elbow has been revised and updated to give you even more coverage of trauma, arthroscopy, soft tissue injury, and joint replacement. The new full-color illustrations and online access to 43 video clips of exams and procedures performed by experts visually enhance an already great resource for both the novice becoming familiar with elbow anatomy and biomechanics and the seasoned surgeon treating difficult elbow problems.
  • Features a technique-focused style and emphasis so you can provide the best hands-on care for your patients.
  • Presents authoritative guidance from leading experts.
  • Covers basic science through practical clinical application for a comprehensive look at the elbow.
  • Features expanded coverage of key topics in trauma, soft tissue procedures, and joint replacement technique to keep you up to date on the latest advances.
  • Supplements the text with new full-color-photos, illustrations, and diagrams for a more instructive and visually appealing approach.
  • Includes 39 video clips (over 2 hours) of exams and procedures—such as calcific tendonitis and RCR margin convergence—performed by the experts online for step-by-step guidance.

Sujets

Ebooks
Savoirs
Medecine
Médecine
Surgical incision
Seronegative arthritis
Nerve compression syndrome
Tenotomy
Screw
Complete
Liver
Disarticulation
Surgical suture
Arthrocentesis
Joint mobilization
Synovectomy
Olecranon bursitis
Continuous passive motion
Replacement
Golfer's elbow
Radial collateral ligament of elbow joint
Tendinosis
Osteochondritis dissecans
Joint replacement
Arthrodesis
Article (publishing)
Arthropathy
Bone grafting
Osteolysis
Epicondylitis
Ossification
Global Assessment of Functioning
Ankylosis
Distal radius fracture
Neoplasm
Inborn error of metabolism
Hip replacement
Muscle contraction
Traumatic brain injury
Acute pancreatitis
Tennis elbow
Internal
Allotransplantation
Orthopedics
Trauma (medicine)
Debridement
Bursitis
Regional anaesthesia
Juvenile idiopathic arthritis
Osteomyelitis
Swelling
Review
Osteoarthritis
Stiffness
Chemical engineer
Orthopedic surgery
Pain management
General anaesthesia
Arthralgia
Lesion
Congenital disorder
Shoulder problem
Soft tissue
Tendinitis
Healing
Medical imaging
Erythrocyte sedimentation rate
Arthroscopy
Rheumatology
Internal medicine
Spasticity
Sports injury
Carpal tunnel syndrome
Complex regional pain syndrome
Cementation
X-ray computed tomography
Cerebral palsy
Infection
Rheumatoid arthritis
Repetitive strain injury
Phylogenetics
Osteoporosis
General surgery
Arthritis
Fractures
Father
Contracture
Elbow
Athlete
Force
Viewpoint
Insight
Supination
Gout
Maladie des exostoses multiples
Release
Pronation
Dislocation
Manual
Fracture
Flexion
Inflammation
Surface
Copyright

Informations

Publié par
Date de parution 25 novembre 2008
Nombre de lectures 0
EAN13 9781437720808
Langue English
Poids de l'ouvrage 9 Mo

Informations légales : prix de location à la page 0,0943€. Cette information est donnée uniquement à titre indicatif conformément à la législation en vigueur.

Exrait

THE ELBOW AND ITS DISORDERS
Fourth Edition

Bernard F. Morrey, MD
Professor of Orthopedic Surgery, Mayo Medical School, Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota

Joaquin Sanchez-Sotelo, MD, PhD
Associate Professor, Department of Orthopedic Surgery, Mayo Graduate School, Rochester, Minnesota
SAUNDERS
Copyright
SAUNDERS ELSEVIER
1600 John F. Kennedy Blvd.
Ste 1800
Philadelphia, PA 19103-2899
THE ELBOW AND ITS DISORDERS
ISBN: 978-1-4160-2902-1
Copyright © 2009 by The Mayo Clinic Foundation
All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Permissions may be sought directly from Elsevier’s Rights Department: phone: (+1) 215 239 3804 (US) or (+44) 1865 843830 (UK); fax: (+44) 1865 853333; e-mail: healthpermissions@elsevier.com . You may also complete your request on-line via the Elsevier website at http://www.elsevier.com/permissions .


Notice
Knowledge and best practice in this field are constantly changing. As new research and experience broaden our knowledge, changes in practice, treatment and drug therapy may become necessary or appropriate. Readers are advised to check the most current information provided (i) on procedures featured or (ii) by the manufacturer of each product to be administered, to verify the recommended dose or formula, the method and duration of administration, and contraindications. It is the responsibility of the practitioner, relying on their own experience and knowledge of the patient, to make diagnoses, to determine dosages and the best treatment for each individual patient, and to take all appropriate safety precautions. To the fullest extent of the law, neither the Publisher nor the Editors assumes any liability for any injury and/or damage to persons or property arising out of or related to any use of the material contained in this book.
The Publisher
Previous editions copyrighted 2000, 1993, 1985 by The Mayo Clinic Foundation.
Library of Congress Cataloging-in-Publication Data
The elbow and its disorders / [edited by] Bernard F. Morrey.–4th ed.
p.; cm.
Includes bibliographical references and index.
ISBN 978-1-4160-2902-1
1. Elbow–Surgery. 2. Elbow–Diseases. 3. Elbow—Fractures. I. Morrey, Bernard F., [DNLM: 1. Elbow Joint–injuries. 2. Joint Diseases. WE 820 E383 2009]
RD558.E43 2009
617.5′74–dc22
2008012878
Acquisitions Editor: Daniel Pepper
Developmental Editor: Ann Ruzycka Anderson
Editorial Assistant: Kim DePaul
Design Direction: Louis Forgione
Marketing Manager: Lisa Damico
Printed in China
Last digit is the print number: 9 8 7 6 5 4 3 2 1
Dedication
As I was preparing the front material for the Fourth Edition of The Elbow and Its Disorders , my father passed away at age 91. It is with great humility as well as a tremendous sense of loss, but also pride that I dedicate this fourth volume to my father, Alfred E. Morrey, Jr. My dad was a chemical engineer and worked in the petroleum industry all of his life. His professional background and skills were instrumental in my formative years in teaching, observation, precision, accuracy, practicality and problem solving. In many ways these features of engineering are not dramatically different from the requirements of the orthopedic surgeon. But, more importantly than this, my father was my role model. He was open-minded and objective and strongly believed in the concept of service. He avoided assuming information as being factual unless it had been demonstrated to be so. But probably the most important characteristic was his desire and stimulus for myself and my siblings to contribute to society and to “give a full days measure”. I have thought of my father regularly throughout my career and with his passing on July 13, 2008, it seems fitting to dedicate this effort to him. He had all three prior volumes proudly displayed in his library.

Bernard F. Morrey, MD
CONTRIBUTORS

Julie E. Adams, MD, Assistant Professor, Department of Orthopaedic Surgery, University of Minnesota School of Medicine, Minneapolis, Minnesota, Fractures of the Olecranon

Robert A. Adams, MA, OPA-C, Adjunct Faculty Clinical Coordinator, University of Wisconsin-La Crosse, La Crosse, Wisconsin, Assistant Professor, Mayo College of Medicine, Rochester, Minnesota, Physician Assistant, Mayo Clinic, Rochester, Minnesota, Linked Total Elbow Arthroplasty in Patients with Rheumatoid Arthritis; Total Elbow Arthroplasty for Primary Osteoarthritis; Wear and Elbow Replacement

Christopher S. Ahmad, MD, Associate Professor, Orthopaedic Surgery, Center for Shoulder, Elbow and Sports Medicine, Columbia University College of Physicians and Surgeons, Attending, Orthopaedic Surgeon, New York Orthopaedic Hospital, Columbia University, New York, New York, Arthroscopy in the Throwing Athlete; Diagnosis and Treatment of Ulnar Collateral Ligament Injuries in Athletes

Gilberto J. Alvarado, MD, Orthopedic Sports Medicine Fellow, Nirschl Orthopaedic Center for Sports Medicine and Joint Reconstruction, Arlington, Virginia, Tennis Elbow Tendinosis

Peter C. Amadio, MD, Professor of Orthopedics, Mayo Clinic College of Medicine, Consultant in Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, Congenital Abnormalities of the Elbow

Kai-Nan An, PhD, Professor, and Director, Biomechanics Laboratory, Mayo Clinic, Rochester, Minnesota, Biomechanics of the Elbow; Functional Evaluation of the Elbow

Karen L. Andrews, MD, Assistant Professor of Physical Medicine and Rehabilitation, College of Medicine, Mayo Clinic, Rochester, Minnesota, Elbow Disarticulation Amputation

Robert D. Beckenbaugh, MD, Professor of Orthopedics, Mayo Clinic, Rochester, Minnesota, Arthrodesis

Richard A. Berger, MD, PhD, Professor of Orthopedic Surgery and Anatomy, Mayo Clinic College of Medicine, Consultant, Division of Hand Surgery, Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, Overuse Syndrome

Thomas H. Berquist, MD, FACR, Professor of Diagnostic Radiology, Mayo Clinic College of Medicine, Rochester, Minnesota, Consultant, Mayo Clinic – Jacksonville, Jacksonville, Florida, Diagnostic Imaging of the Elbow

Allen T. Bishop, MD, Professor of Orthopedic Surgery, Mayo Clinic College of Medicine, Consultant, Department of Orthopedic Surgery, and Chair, Division of Hand Surgery, Mayo Clinic, Rochester, Minnesota, Soft Tissue Coverage of the Elbow; Flaccid Dysfunction of the Elbow

Kenneth P. Butters, MD, Consultant, Hand Surgery, Department of Orthopedic Surgery, University of Oregon, Eugene, Oregon, Septic Arthritis

Andrea Celli, MD, Consultant Orthopaedic and Traumatology Surgeon, Orthopaedic and Traumatology Department, University of Modena e Reggio Emilia, Modena, Italy, Triceps Insufficiency Following Total Elbow Arthroplasty

Emilie Cheung, MD, Assistant Professor, Medical Center Line, and Stanford Hospital and Clinics, Stanford University, Stanford, California, Treatment of the Infected Total Elbow Arthroplasty

Akin Cil, MD, Assistant Professor of Orthopaedics, Department of Orthopaedic Surgery, University of Missouri Kansas City, Attending Surgeon, Department of Orthopaedic Surgery, Truman Medical Center, Kansas City, Missouri, Synovectomy of the Elbow

Mark S. Cohen, MD, Professor, Director, Orthopaedic Education, and Director, Section of Hand and Elbow Surgery, Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, Illinois, Advanced Techniques: Arthroscopic Management of Lateral Epicondylitis

Patrick M. Connor, MD, Clinical Faculty, Shoulder and Elbow Surgery/Sports Medicine, and Trauma Surgery, Orthopaedic Surgery Residency Program, Carolinas Medical Center, Charlotte, North Carolina, Total Elbow Arthroplasty for Juvenile Rheumatoid Arthritis

William P. Cooney, MD, Professor of Orthopedics, Mayo Clinic, Rochester, Minnesota, Elbow Arthroplasty: Historical Perspective and Emerging Concepts

Ralph W. Coonrad, MD, Associate Clinical Professor, Department of Orthopedic Surgery, Duke University, Medical Director Emeritus, Lenox Baker Children’s Hospital, Duke University, Durham, North Carolina, Nonunion of the Olecranon and Proximal Ulna

Joshua S. Dines, MD, Clinical Instructor, Orthopedic Surgery, Weill Cornell Medical College, Assistant Attending, Sports Medicine and Shoulder Service, The Hospital for Special Surgery, New York, New York, Articular Injuries in the Athlete

James H. Dobyns, MD, Professor of Orthopedics, and Emeritus Staff, Mayo Clinic College of Medicine, Rochester, Minnesota, and University of Texas San Antonio Health Science Center, San Antonio, Texas, Congenital Abnormalities of the Elbow

Neal S. ElAttrache, MD, Associate Clinical Professor, Department of Orthopaedics, Keck School of Medicine, University of Southern California, Director, Sports Medicine Fellowship, Kerlan-Jobe Orthopaedic Clinic, Los Angeles, California, Arthroscopy in the Throwing Athlete; Diagnosis and Treatment of Ulnar Collateral Ligament Injuries in Athletes; Articular Injuries in the Athlete

Larry D. Field, MD, Clinical Instructor, Department of Orthopaedic Surgery, University of Mississippi School of Medicine, Director, Upper Extremity Service, Mississippi Sports Medicine and Orthopaedic Center, Jackson, Mississippi, Diagnostic Arthroscopy: Indications, Portals, and Techniques; Management of Loose Bodies and Other Limited Procedures; Arthroscopic Management of the Stiff Elbow

Gerard T. Gabel, MD, Clinical Associate Professor, Department of Orthopedic Surgery, Baylor College of Medicine, Houston, Texas, Medial Epicondylitis

David R.J. Gill, MD, ChB, FRACS, Joondalup Health Campus, Joondalup, Western Australia, Australia, Linked Total Elbow Arthroplasty in Patients with Rheumatoid Arthritis

E. Richard Graviss, MD, Professor of Radiology, St. Louis University School of Medicine, Pediatric Radiology, Cardinal Glennon Children’s Hospital, St. Louis, Missouri, Imaging of the Pediatric Elbow

G. Dean Harter, MD, Associate, Department of Orthopaedic Surgery, Chief, Shoulder and Elbow Institute, Program Director, Orthopaedic Surgery Residency, Geisinger Health System, Danville, Pennsylvania, Ectopic Ossification About the Elbow

Alan D. Hoffman, MD, Associate Professor of Radiology, Mayo Clinic College of Medicine, Consultant in Radiology – Pediatric Radiology, Mayo Clinic, Rochester, Minnesota, Imaging of the Pediatric Elbow

Terese T. Horlocker, MD, Professor of Anesthesiology and Orthopedics, Mayo Clinic, Rochester, Minnesota, General and Regional Anesthesia and Postoperative Pain Control

Jeffery S. Hughes, MB, FRACS, Orthopaedic Consultant, North Shore Private Hospital, Sydney, Australia, Injury of the Flexors of the Elbow: Biceps Tendon Injury; Unlinked Arthroplasty: Distal Humeral Hemiarthroplasty

Srinath Kamineni, MBBCh, FRCS-Ed, FRCS-Orthopaedics and Trauma, PhD, Professor of Bioengineering, Brunel University – School of Engineering and Design, Consultant Elbow, Shoulder, Upper Limb Surgeon, and Clinical Lead, Upper Limb Unit, Cromwell Hospital, London, United Kingdom, Distal Humeral Fractures–Acute Total Elbow Arthroplasty

Graham J.W. King, MD, MSc, FRCSC, Professor, Department of Surgery, University of Western Ontario, Chief of Orthopaedic Surgery, St. Joseph’s Health Centre, London, Ontario, Canada, Unlinked Arthroplasty: Unlinked Total Elbow Arthroplasty; Unlinked Arthroplasty: Convertible Total Elbow Arthroplasty; Revision of Failed Total Elbow Arthroplasty with Osseous Integrity

Sandra L. Kopp, MD, Assistant Professor of Anesthesiology, Mayo Clinic, Rochester, Minnesota, General and Regional Anesthesia and Postoperative Pain Control

Tomasz K.W. Kozak, FRACS, West Perth, Western Australia, Australia, Total Elbow Arthroplasty for Primary Osteoarthritis

Mikko Larsen, MD, Research Fellow, Microvascular Research Laboratory, Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, Resident in Training, Department of Plastic and Reconstructive Surgery, V.U. Medical Center, Amsterdam, The Netherlands, Flaccid Dysfunction of the Elbow

A. Noelle Larson, MD, Resident in Orthopedics, Department of Orthopedics, Mayo Clinic, Rochester, Minnesota, Hinged External Fixators of the Elbow; Interposition Arthroplasy of the Elbow

Susan G. Larson, MS, PhD, Professor, Department of Anatomical Sciences, School of Medicine, Stony Brook University Medical Center, Stony Brook, New York, Phylogeny

Brian P. Lee, MD, Orthopaedic Associates, Singapore, Singapore, Wear and Elbow Replacement

Robert L. Lennon, DO, Associate Professor of Anesthesiology, Mayo Medical School, Supplemental Consultant, Mayo Clinic, Rochester, Minnesota, General and Regional Anesthesia and Postoperative Pain Control

R. Merv Letts, MD, MSc, FRCSC, FACS, Consultant Pediatric Orthopaedic Surgeon, Sheikh Khalifa Medical City, Abu Dhabi, United Arab Emirates, Dislocations of the Child’s Elbow

Harvinder S. Luthra, MD, Professor of Medicine, Department of Rheumatology, Mayo Clinic, Rochester, Minnesota, Rheumatoid Arthritis

Alex A. Malone, MBBS, MRCS (Eng), FRCS (Tr & Orth), Consultant Orthopaedic Surgeon, Christchurch Hospital, Canterbury, New Zealand, Senior Lecturer in Orthopaedics with an interest in Upper Limb Surgery, Christchurch School of Medicine, Otago University, New Zealand, Honorary Consultant, Shoulder and Elbow Unit, The Royal National Orthopaedic Hospital, Stanmore, United Kingdom, Honorary Lecturer, Department of Surgery, University College London, London, United Kingdom, Phylogeny

Pierre Mansat, MD, PhD, Professor of Orthopedics and Traumatology, Faculté Medecine Toulouse/Purpan, Université Paul Sabatier, and Service d’Orthopedie/Traumatologie, Unité du Membre Superieur, Centre Hospitalier Universitaire Purpan, Toulouse, France, Extrinsic Contracture: Lateral and Medial Column Procedures

Thomas G. Mason, MD, Associate Professor of Internal Medicine and Pediatrics, Mayo Clinic College of Medicine, Consultant in Adult and Pediatric Rheumatology, Mayo Clinic, Rochester, Minnesota, Seronegative Inflammatory Arthritis

Glen A. McClung, II, MD, Commonwealth Orthopaedic Surgeons, Lexington, Kentucky, Diagnostic Arthroscopy: Indications, Portals, and Techniques

Amy L. McIntosh, MD, Associate Clinical Professor, Mayo Clinic, Rochester, Minnesota, Complications of Supracondylar Fractures of the Elbow

Steven L. Moran, MD, Assistant Professor of Orthopedics and Plastic Surgery, Mayo College of Medicine, and Mayo Clinic, Rochester, Minnesota, Soft Tissue Coverage of the Elbow

Bernard F. Morrey, MD, Professor of Orthopedic Surgery, Mayo Medical School; Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, Anatomy of the Elbow Joint; Biomechanics of the Elbow; Physical Examination of the Elbow; Functional Evaluation of the Elbow; Surgical Exposures of the Elbow; Principles of Elbow Rehabilitation; Splints and Bracing at the Elbow; Proximal Ulnar Fractures in Children; Dislocations of the Child’s Elbow; Post-Traumatic Elbow Stiffness in Children; Radial Head Fracture: General Considerations, Conservative Treatment, and Open Reduction and Internal Fixation; Radial Head Fracture: Prosthetic Radial Head Replacement; Nonunion of the Olecranon and Proximal Ulna; Coronoid Process and Monteggia Fractures; Complex Instability of the Elbow; Chronic Unreduced Elbow Dislocation; Ectopic Ossification About the Elbow; Extrinsic Contracture: Lateral and Medial Column Procedures; Hinged External Fixators of the Elbow; Injury of the Flexors of the Elbow: Biceps Tendon Injury; Rupture of the Triceps Tendon; Complications of Elbow Arthroscopy; The Future of Arthroscopy of the Elbow; Medial Epicondylitis; Surgical Failure of Tennis Elbow; Elbow Arthroplasty: Historical Perspective and Emerging Concepts; Unlinked Arthroplasty: Radiohumeral Arthrosis: Anconeus Arthroplasty and Capitellar Prosthetic Replacement; Linked Elbow Arthroplasty: Rationale, Indications, and Surgical Technique; Linked Total Elbow Arthroplasty in Patients with Rheumatoid Arthritis; Total Elbow Arthroplasty for Juvenile Rheumatoid Arthritis; Semiconstrained Elbow Replacement: Results in Traumatic Conditions; Total Elbow Arthroplasty as a Salvage for the Fused Elbow; Total Elbow Arthroplasty for Primary Osteoarthritis; Complications of Elbow Replacement Arthroplasty; Treatment of the Infected Total Elbow Arthroplasty; Triceps Insufficiency Following Total Elbow Arthroplasty; Wear and Elbow Replacement; Revision of Failed Total Elbow Arthroplasty with Osseous Integrity; Revision of Failed Total Elbow Arthroplasty with Osseous Deficiency; Nonimplantation Salvage of Severe Elbow Dysfunction; Synovectomy of the Elbow; Interposition Arthroplasty of the Elbow; Primary Osteoarthritis: Ulnohumeral Arthroplasty; Septic Arthritis; Neoplasms of the Elbow; Loose Bodies; Bursitis; The Elbow in Metabolic Disease

Matthew Morrey, MD, Senior Orthopaedic Resident, Department of Orthopaedic Surgery, Mayo Clinic, Rochester, Minnesota, Hinged External Fixators of the Elbow

Scott J. Mubarak, MD, Clinical Professor, Department of Orthopedics, University of California, San Diego, Director of Orthopedic Program, Children’s Hospital, San Diego, California, Complications of Supracondylar Fractures of the Elbow

Robert P. Nirschl, MD, MS, Associate Clinical Professor, Georgetown University School of Medicine, Washington, DC, Director, Sports Medicine Fellowship Programs, Nirschl Orthopaedic Center for Sports Medicine and Joint Reconstruction, Arlington, Virginia, Attending Orthopedic Surgeon, Virginia Hospital Center, Arlington, Virginia, Tennis Elbow Tendinosis

Shawn W. O’Driscoll, PhD, MD, Professor of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, Continuous Passive Motion; Current Concepts in Fractures of the Distal Humerus; Elbow Dislocations; Complex Instability of the Elbow

Nicole M. Orzechowski, DO, Instructor of Internal Medicine, Mayo Clinic College of Medicine; Mayo Clinic, Rochester, Minnesota, Seronegative Inflammatory Arthritis

Panayiotis J. Papagelopoulos, MD, DSc, Associate Professor of Orthopaedics, Athens University Medical School, Consultant, First Department of Orthopaedics, Attikon University General Hospital, Athens University Medical School, Athens, Greece, Nonunion of the Olecranon and Proximal Ulna

Hamlet A. Peterson, MD, MS, Emeritus Professor of Orthopedic Surgery, Mayo Medical School, Emeritus Consultant in Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, Physeal Fractures of the Elbow

Douglas J. Pritchard, AB, MS, MD, Orthopedic Surgery, Retired, Mayo Clinic, Rochester, Minnesota, Neoplasms of the Elbow

Matthew L. Ramsey, MD, Associate Professor of Orthopaedic Surgery, Thomas Jefferson University, and Rothman Institute, Philadelphia, Pennsylvania, Total Elbow Arthroplasty for Distal Humerus Nonunion and Dysfunctional Instability

William D. Regan, MD, FRCS(C), Associate Professor, Department of Orthopaedics, University of British Columbia, Associate Head, Department of Orthopaedics, and Head, Division of Upper Extremity Surgery, University Hospital, Vancouver, British Columbia, Canada, Physical Examination of the Elbow; Coronoid Process and Monteggia Fractures

Anthony A. Romeo, MD, Associate Professor, and Director, Section of Shoulder and Elbow, Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, Illinois, Advanced Techniques: Arthroscopic Management of Lateral Epicondylitis

Joaquin Sanchez-Sotelo, MD, PhD, Associate Professor of Orthopedics, Mayo Clinic College of Medicine, Consultant in Orthopedic Surgery, Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, Nonunion and Malunion of Distal Humerus Fractures; Lateral Collateral Ligament Insufficiency; Total Elbow Arthroplasty for Distal Humerus Nonunion and Dysfunctional Instability; Revision of Failed Total Elbow Arthroplasty with Osseous Deficiency; Hematologic Arthritis

Felix H. Savoie, III, MD, Lee Schlesinger Professor, Shoulder, Elbow and Sports Surgery, Department of Orthopaedic Surgery, Tulane University, Chair, Division of Sports Medicine, Tulane Institute of Sports Medicine, New Orleans, Louisiana, Diagnostic Arthroscopy: Indications, Portals, and Techniques; Management of Loose Bodies and Other Limited Procedures; Arthroscopic Management of the Stiff Elbow; Advanced Techniques: Arthroscopic Radial Ulnohumeral Ligament Reconstruction for Posterolateral Rotatory Instability of the Elbow; The Future of Arthroscopy of the Elbow

Alberto G. Schneeberger, MD, Privatdozent, University of Zurich, Consultant, Shoulder and Elbow Surgery, Zurich, Switzerland, Semiconstrained Elbow Replacement: Results in Traumatic Conditions

William J. Shaughnessy, MS, MD, Associate Professor of Orthopedic Surgery, Mayo Medical School, Member, Division of Pediatric Orthopedics, Mayo Clinic, Rochester, Minnesota, Osteochondritis Dissecans

Alexander Y. Shin, MD, Professor, Orthopaedic Surgery, Mayo Clinic School of Medicine, Consultant, Orthopaedic Surgery, Mayo Clinic, Rochester, Minnesota, Flaccid Dysfunction of the Elbow

Thomas C. Shives, MD, Professor of Orthopedics, Mayo Clinic, Rochester, Minnesota, Elbow Disarticulation Amputation

Jay Smith, MD, Associate Professor of Physical Medicine and Rehabilitation, Mayo Clinic College of Medicine, Consultant, Department of Physical Medicine and Rehabilitation, Mayo Clinic, Rochester, Minnesota, Principles of Elbow Rehabilitation

Robert J. Spinner, MD, Professor, Departments of Neurosurgery, Orthopedics and Anatomy, Mayo Clinic College of Medicine, Consultant, Department of Neurologic Surgery and Orthopedics, Mayo Clinic, Rochester, Minnesota, Nerve Entrapment Syndromes

Anthony A. Stans, MD, Assistant Professor, and Chair, Division of Pediatric Orthopedics, Mayo Clinic, Rochester, Minnesota, Supracondylar Fractures of the Elbow in Children; Fractures of the Neck of the Radius in Children; Proximal Ulnar Fractures in Children; Post-Traumatic Elbow Stiffness in Children

Scott P. Steinmann, MD, Consultant, Professor of Orthopedics Mayo Clinic College of Medicine, Rochester, Minnesota, Fractures of the Olecranon

J. Clarke Stevens, MD, Professor of Neurology, Mayo Medical School, Rochester, Minnesota, Neurotrophic Arthritis

Kristen B. Thomas, MD, Assistant Professor of Radiology, Mayo Clinic College of Medicine, Consultant in Radiology – Pediatric Radiology, Mayo Clinic, Rochester, Minnesota, Imaging of the Pediatric Elbow

Nho V. Tran, MD, Assistant Professor of Plastic Surgery, Mayo College of Medicine, and Mayo Clinic, Rochester, Minnesota, Soft Tissue Coverage of the Elbow

Stephen D. Trigg, MD, Associate Professor, Orthopaedics and Hand Surgery, Mayo Clinic Medical School Hand Surgery, Mayo Medical School, Rochester, Minnesota, Hand Surgeon, Department of Orthopaedics, and Medical Director, Outpatient Surgery Center, Mayo Clinic, Jacksonville, Florida, Pain Dysfunction Syndrome

K. Krishnan Unni, MD, Emeritus Professor of Pathology, Departments of Anatomic Pathology, Orthopedic Oncology, and Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, Neoplasms of the Elbow

Francis Van Glabbeek, MD, PhD, Professor of Functional Anatomy and Orthopaedics, University of Antwerp, Vice Chair, Department of Orthopaedics and Traumatology, University Hospital Antwerp, Antwerp, Belgium, Radial Head Fracture: General Considerations, Conservative Treatment, and Open Reduction and Internal Fixation

Ann E. Van Heest, MD, Professor, Department of Orthopaedic Surgery, University of Minnesota, Minneapolis; Gillette Children’s Specialty Healthcare, St. Paul, Minnesota, Spastic Dysfunction of the Elbow

Roger P. van Riet, MD, PhD, Orthopaedic Surgeon, Elbow Surgery, Monica Hospital, Deurne, Antwerp, Belgium, Radial Head Fracture: General Considerations, Conservative Treatment, and Open Reduction and Internal Fixation

Ilya Voloshin, MD, Assistant Professor, University of Rochester, Director, Shoulder and Elbow Service, University of Rochester Medical Center, Rochester, New York, Complications of Elbow Replacement Arthroplasty

Ken Yamaguchi, MD, Sam and Marilyn Fox Distinguished Professor of Orthopaedic Surgery, and Chief, Shoulder and Elbow Service, Washington University School of Medicine, St. Louis, Missouri, Treatment of the Infected Total Elbow Arthroplasty

Mark E. Zobitz, MS, Assistant Professor, Biomechanics Laboratory, Mayo Clinic, Rochester, Minnesota, Biomechanics of the Elbow
PREFACE
Since the first edition of The Elbow and Its Disorders in 1983 I am extremely proud to hear such comments regarding the original and previous efforts such as “the definitive word in elbow surgery”. Such statements and confidence is a source of tremendous pride and also motivation to continue to improve. In the spirit of the original goal of providing a source of reliable information that will im-prove patient care, we continue to be focused on this initial desire to provide clear, concise, current, accurate, relevant and intelligible information that is easily accessible.
I have a simple personal requirement for the timing of subsequent editions of this book. This is to wait until I feel as though there has been sufficient additional information to justify another volume. This requirement has been met with this particular effort.
Thus, I am very pleased along with my co-authors to have completed the current volume. The overall organization, hope and effort to be a comprehensive reference has been maintained with an increased emphasis on surgical technique which is an ever growing and relevant need of the orthopedic community. We are, therefore, specifically pleased to offer video clips in a number of chapters that do complement and enhance the practical and useful learning experience.
The exciting advances in elbow arthroscopy are more extensively explored in the current volume. Innovative opportunities with regard to prosthetic joint replacement are also discussed in the current volume, along with nonprosthetic options such as anconeus arthroplasty. In fact we are pleased to observe considerable enhancement in the majority of chapters. As always I am deeply appreciative and humbled by those who have contributed material, thoughts, and insights over the years, particularly Doctors O’Driscoll, Steinmann, Sanchez-Sotelo and my other partners at the Mayo Clinic.
Finally, I should note that this edition is an opportunity to introduce my partner and colleague, Joaquin Sanchez-Sotelo, who has assisted me in the preparation of the current volume, and who has shown an insightful and substantive commitment to the practice of elbow surgery. It remains our hope that the reader will continue to find this text relevant both from the perspective of arriving at a diagnosis of a difficult problem, understanding the options and potential outcome of various interventions, as well insight with regard to how surgical techniques might be executed.

Bernard F. Morrey, MD
Acknowledgment
I wish to acknowledge with genuine appreciation all the input and insight I received from orthopedic colleagues around the world, especially my colleagues, residents and fellows at the Mayo Clinic. I also wish to express my most sincere appreciation to Professor Gerber for the thoughtful and gracious comments which he made in the “forward” of this edition.
The administrative efforts of my associate of 30 years, Bob Adams, to help find that one unique patient or x-ray has always been a tremendous and an essential asset, as is the secretarial and administrative efforts of my secretary, Sherry Koperski, and the numerous details and competencies provided by Donna Riemersma in the preparation of this manuscript.
Finally, and as always, I want to expressly acknowledge my wife, Carla, who has now lived through and encouraged me in the preparation of four editions of “Disorders”. I am deeply appreciative of all the support I have received from Carla, our children, and from the profession throughout my career.
FOREWORD
Via internet we can gain access to almost any medical data within a few mouse clicks. The most recent Journal articles including illustrations are at hand and most data banks allow us to get immediate access to related articles. If ever we decide to review an older publication not yet available in PDF format, it can be ordered within hours or very few days. Details of current surgical techniques are now reviewed in top quality video and DVD productions coming from leading international experts. The question is therefore inevitable whether the concept of a textbook is out of date and in fact, out of place. Unfortunately, many current textbooks are an assiduous compilation of more or less well digested original articles allowing at best for a cookbook approach to orthopaedics. These many textbooks may decorate a bookshelf but add nothing to the impressive number of references they quote and are superfluous.
What could the value of a current textbook be and why would we use it? In this period of time, which Kipling characterizes by the probably unassailable lead of knowledge over wisdom, in a time where orthopaedics is taught in “training” programs – although we know that training refers to dogs and education refers to people – we, the upper extremity surgeons who all have a copy of the Third wait for the Fourth (!) Edition of “The Elbow and its Disorders”. Our expectations are living proof that there remains a role for a textbook, because there is a role for education, for educators, as role models who teach medicine based on an immense body of knowledge with wisdom, experience and compassion. There is a role for an instrument which puts scientific knowledge into perspective and helps us to apply knowledge most effectively to our patients.
Dr. Morrey has spent decades observing, describing, and defining elbow problems. In a very systematic fashion, he has studied the identified problems with collaborators and friends in the laboratory, and brought his insight back into clinical practice. Subsequently not only he and his pupils but surgeons throughout the world have validated and do validate the respective contributions in their patients. This textbook incorporates the knowledge gained from these and many other investigations. It discloses details which have taken the authors years to understand and apply. Yes, this textbook is comprehensive andprecise and yes, it certainly is the gold standard for elbow surgery on all continents.
But I see the unique value of this book elsewhere. I see it in sharing an approach to clinical problem solving. Dr. Morrey shows how to identify a problem, how to evaluate a problem and finally how to solve it. The text may not be able to impart the human qualities of the editor, which certainly are large contributors of his success with very difficult patient problems. But the text unequivocally clearly states that orthopaedic surgery is not a manual but an intellectual discipline and that excellent orthopaedic care is an art based on science.
Bernie, this textbook is a further testimony to you as a physician – scientist, educator and role model. It has been one of the privileges of my lifetime to meet you early in my career and to benefit from your wisdom and advice. For my next elbow problem, I – as many others – will consult this textbook and I am sure it will not only give me data but it will give me understanding. For any other very difficult problem, I hope I can continue to call you.

Christian Gerber, MD, FRCS(hon), Professor and Chair, Department of Orthopaedics, University of Zürich, Zürich, Switzerland
Table of Contents
Instructions for online access
Copyright
Dedication
CONTRIBUTORS
PREFACE
Acknowledgment
FOREWORD
PART I: Fundamentals and General Considerations
Chapter 1: Phylogeny
Chapter 2: Anatomy of the Elbow Joint
Chapter 3: Biomechanics of the Elbow
PART II: Diagnostic Considerations
Chapter 4: Physical Examination of the Elbow
Chapter 5: Functional Evaluation of the Elbow
Chapter 6: Diagnostic Imaging of the Elbow
PART III: Surgery and Rehabilitation
Chapter 7: Surgical Exposures of the Elbow
Chapter 8: General and Regional Anesthesia and Postoperative Pain Control
Chapter 9: Principles of Elbow Rehabilitation
Chapter 10: Continuous Passive Motion
Chapter 11: Splints and Bracing at the Elbow
PART IV: Conditions Affecting the Child’s Elbow
Chapter 12: Imaging of the Pediatric Elbow
Chapter 13: Congenital Abnormalities of the Elbow
Chapter 14: Supracondylar Fractures of the Elbow in Children
Chapter 15: Complications of Supracondylar Fractures of the Elbow
Chapter 16: Physeal Fractures of the Elbow
Chapter 17: Fractures of the Neck of the Radius in Children
Chapter 18: Proximal Ulnar Fractures in Children
Chapter 19: Osteochondritis Dissecans
Chapter 20: Dislocations of the Child’s Elbow
Chapter 21: Post-Traumatic Elbow Stiffness in Children
PART V: Adult Trauma
Section A: Fractures and Dislocations
Chapter 22: Current Concepts in Fractures of the Distal Humerus
Chapter 23: Nonunion and Malunion of Distal Humerus Fractures
Chapter 24: Radial Head Fracture
Chapter 25: Fractures of the Olecranon
Chapter 26: Nonunion of the Olecranon and Proximal Ulna
Chapter 27: Coronoid Process and Monteggia Fractures
Chapter 28: Elbow Dislocations
Chapter 29: Complex Instability of the Elbow
Chapter 30: Chronic Unreduced Elbow Dislocation
Chapter 31: Ectopic Ossification About the Elbow
Section B: Soft Tissue Considerations
Chapter 32: Extrinsic Contracture: Lateral and Medial Column Procedures
Chapter 33: Hinged External Fixators of the Elbow
Chapter 34: Injury of the Flexors of the Elbow: Biceps Tendon Injury
Chapter 35: Rupture of the Triceps Tendon
Chapter 36: Soft Tissue Coverage of the Elbow
PART VI: Sports and Overuse Injuries to the Elbow
Section A: Arthroscopy
Chapter 37: Diagnostic Arthroscopy: Indications, Portals, and Techniques
Chapter 38: Management of Loose Bodies and Other Limited Procedures
Chapter 39: Arthroscopy in the Throwing Athlete
Chapter 40: Arthroscopic Management of the Stiff Elbow
Chapter 41: Advanced Techniques
Chapter 42: Complications of Elbow Arthroscopy
Chapter 43: The Future of Arthroscopy of the Elbow
Section B: Muscle and Tendon Trauma
Chapter 44: Tennis Elbow Tendinosis
Chapter 45: Medial Epicondylitis
Chapter 46: Surgical Failure of Tennis Elbow
Chapter 47: Diagnosis and Treatment of Ulnar Collateral Ligament Injuries in Athletes
Chapter 48: Lateral Collateral Ligament Insufficiency
Chapter 49: Articular Injuries in the Athlete
Chapter 50: Overuse Syndrome
PART VII: Reconstructive Procedures of the Elbow
Section A: Joint Replacement Arthroplasty
Chapter 51: Elbow Arthroplasty: Historical Perspective and Emerging Concepts
Chapter 52: Unlinked Arthroplasty
Chapter 53: Linked Elbow Arthroplasty: Rationale, Indications, and Surgical Technique
Chapter 54: Linked Total Elbow Arthroplasty in Patients with Rheumatoid Arthritis
Chapter 55: Total Elbow Arthroplasty for Juvenile Rheumatoid Arthritis
Chapter 56: Distal Humeral Fractures–Acute Total Elbow Arthroplasty
Chapter 57: Semiconstrained Elbow Replacement: Results in Traumatic Conditions
Chapter 58: Total Elbow Arthroplasty as a Salvage for the Fused Elbow
Chapter 59: Total Elbow Arthroplasty for Distal Humerus Nonunion and Dysfunctional Instability
Chapter 60: Total Elbow Arthroplasty for Primary Osteoarthritis
Chapter 61: Complications of Elbow Replacement Arthroplasty
Chapter 62: Treatment of the Infected Total Elbow Arthroplasty
Chapter 63: Triceps Insufficiency Following Total Elbow Arthroplasty
Chapter 64: Wear and Elbow Replacement
Chapter 65: Revision of Failed Total Elbow Arthroplasty with Osseous Integrity
Chapter 66: Revision of Failed Total Elbow Arthroplasty with Osseous Deficiency
Chapter 67: Nonimplantation Salvage of Severe Elbow Dysfunction
Section B: Nonprosthetic Reconstruction
Chapter 68: Synovectomy of the Elbow
Chapter 69: Interposition Arthroplasty of the Elbow
Chapter 70: Arthrodesis
Chapter 71: Flaccid Dysfunction of the Elbow
Chapter 72: Spastic Dysfunction of the Elbow
Chapter 73: Elbow Disarticulation Amputation
PART VIII: Septic and Nontraumatic Conditions
Chapter 74: Rheumatoid Arthritis
Chapter 75: Seronegative Inflammatory Arthritis
Chapter 76: Primary Osteoarthritis: Ulnohumeral Arthroplasty
Chapter 77: Septic Arthritis
Chapter 78: Hematologic Arthritis
Chapter 79: Neurotrophic Arthritis
Chapter 80: Nerve Entrapment Syndromes
Chapter 81: Pain Dysfunction Syndrome
Chapter 82: Neoplasms of the Elbow
Chapter 83: Loose Bodies
Chapter 84: Bursitis
Chapter 85: The Elbow in Metabolic Disease
INDEX
PART I
Fundamentals and General Considerations
CHAPTER 1 Phylogeny

Alex A. Malone, Susan G. Larson

INTRODUCTION
The human elbow forms the link between brachium and forearm, controlling length of reach and orientation of the hand, and is one of our most distinctive anatomical regions. An appreciation of elbow phylogeny compliments anatomic knowledge in three ways: (1) it demonstrates how the elbow has evolved to facilitate specific functional demands, such as suspensory locomotion and dexterous manipulation; (2) it explains the functional significance of each morphologic feature; and (3) it assists in predicting the consequences of loss of such features through disease, injury, or treatment.
Most of the characteristic features of the human elbow significantly predate the appearance of modern Homo sapiens . In fact, current evidence suggests that this morphology can be traced back to the common ancestor of humans and apes, extant about 15 to 20 million years ago (mya).

EVOLUTION OF THE VERTEBRATE ELBOW
The distal humerus of pelycosaurs, the late Paleozoic (255 to 235 mya) reptiles that probably gave rise to more advanced mammal-like reptiles, possessed a bulbous capitellum laterally and medially. The articulation with the ulna was formed by two distinct surfaces: a slightly concave ventral surface and a more flat dorsal surface ( Fig. 1-1 ). 11 The proximal articular surface of the ulna was similarly divided into two surfaces separated by a low ridge. Reconstruction of the forelimb of these reptiles suggests that they walked with limbs splayed out to the side. The humerus was held more or less horizontal, the elbow flexed to 90 degrees, and the forearm was sagittally oriented. Forward motion was brought about by rotation of the humerus around its long axis, which propelled the body forward relative to the fixed forefoot. Elbow flexion and extension probably were useful only in side-to-side motions. The ulnohumeral joint, with its dual articular surfaces, was well suited to resist the valgus/varus stress produced by humeral rotation, and the proximal end of the radius was flat and triangular, precluding pronosupination. It appears, therefore, that stability rather than mobility was the major functional characteristic of the elbow of these late Paleozoic reptiles.

FIGURE 1-1 The major evolutionary stages in the development of the elbow joint from pelycosaurs to advanced mammals. The distal ends of the humeri are shown on the left, and the corresponding radius and ulna are on the right. The form of the pelycosaur elbow was designed to maximize stability. Subsequent evolutionary stages show accommodations to increasing mobility.
(Adapted from Jenkins, F. A. Jr.: The functional anatomy and evolution of the mammalian humeroulnar articulation. Am. J. Anat. 137:281, 1973.)
Cynodonts, the more immediate ancestors of mammals from the Permo-Triassic period (235 to 160 mya), had their limbs underneath their bodies rather than at the sides. The distal humeral articular surface consisted of radial and ulnar condyles separated by a shallow groove (see Fig. 1-1 ). The proximal ulnar articular surface was an elongate spoon shape for articulation with the humeroulnar condyle. The lateral flange on the ulna for articulation with the radius was separated from this surface by a low ridge. This ridge articulated with the groove between the radial and ulnar condyles displaying some features in common with the “tongue and groove” (trochleariform) type of humeroulnar articulation characteristic of many modern mammals.
Early mammals from the Triassic (210 to 160 mya) and Jurassic (160 to 130 mya) periods also had radial and ulnar condyles. However, the radial condyle was more protuberant than the ulnar, and the ulnar condyle was more linear and obliquely oriented (see Fig. 1-1 ). The two condyles were separated by an intercondylar groove. The ulnar notch had articular surfaces for both the ulnar and the radial condyles, each matching the configuration of the corresponding humeral surface. The oblique orientation of the humeroulnar joint resembled a spiral configuration, which helped to keep forearm movement in a sagittal plane as the humerus underwent a compound motion involving adduction, elevation, and rotation during propulsion.
The trochleariform distal humeral articular surface in modern mammals largely came about by widening the intercondylar groove and the development of a ridge within it (see Fig. 1-1, bear ). The articular surface on the proximal ulna is oblique in orientation, and the distal half retains an articulation with the ulnar condyle. This spiral trochlear configuration allows the forearm to move in a sagittal plane while maintaining the stability of ulnohumeral contact through the cam effect of the ulnar condyle during humeral rotation.
Most small noncursorial mammals have maintained the spiral configuration of the trochlear articular surface observed in early mammals. In larger and more cursorial mammals, the trochlea displays various ridges and is narrower to improve stability, although at the expense of joint mobility. Only in the hominoid primates, which include humans, chimpanzees, gorillas, orangutans, and gibbons, is the medial aspect of the distal humeral articular surface truly trochleariform. In the next section, we discuss the functional significance of the unique aspects of the hominoid elbow joint.

COMPARATIVE PRIMATE ANATOMY OF THE ELBOW REGION
Much of what follows is taken from the detailed studies of Rose. 20, 21 The humeral trochlea may be cylindrical, conical, or trochleariform in nonhuman primates. 21 The trochlea is conical in some prosimians, but a cylindrical trochlea seems to be the most common shape and is observed in most prosimians and New World monkeys. The trochlea is also cylindrical in most Old World monkeys but with a pronounced medial flange or keel that is best developed anterodistally ( Fig. 1-2 ). Only in apes and humans is the trochlea truly trochleariform, possessing medial and lateral ridges all around the trochlear margins, which contribute to the stability of the ulnohumeral joint, substituting for the radiohumeral joint, which is freed for pronosupination throughout the flexion range. 11, 20 In most species, the articular surface of the trochlea expands posteriorly to the area behind the capitellum. In larger monkeys, the lateral edge of the posterior trochlear surface projects to form a keel that extends up the lateral wall of the olecranon fossa (see Fig. 1-2 ). In hominoids, this keel is a continuation of the lateral trochlear ridge and helps form a sharp lateral margin of the olecranon fossa, providing resistance to varus and internal rotation in extension. 20 . 21

FIGURE 1-2 Distal humeri of a baboon, a chimpanzee, and a human from anterior, distal, and posterior aspects. The lateral trochlear ridge is well developed in both the human and the chimpanzee but is largely nonexistent in the baboon. The baboon humerus displays prominent flanges anteromedially and posterolaterally. The lateral epicondyle is placed higher in the chimpanzee than in the human and displays a more strongly developed supracondylar crest.
The trochlear notch of the ulna generally mirrors the shape of the humeral trochlea. In humans and apes, the notch has medial and lateral surfaces separated by a ridge that articulates with the trochlear groove ( Fig. 1-3 ). 20, 21

FIGURE 1-3 Proximal ulnae of a baboon, a chimpanzee, and a human. The trochlear notch is wider in the chimpanzee and the human and displays a prominent ridge for articulation with the trochlear groove. In addition, the radial notch faces laterally in the chimp and human, unlike in the baboon, in which it faces more anteriorly.
The differences seen in the configuration of the humeroulnar joint across primate species reflect contrasting requirements for stabilization with different forms of limb use. In most monkeys, the humeroulnar joint is in its most stable configuration in a partially flexed position owing to the development of the medial trochlear keel anterodistally and the lateral keel posteriorly. 20
It is not surprising that this position of maximum stability is the one assumed by the forelimb during the weight-bearing phase of quadrupedal locomotion. The anterior orientation of the trochlear notch is a direct adaptation to weight bearing with a partially flexed limb. However, such an orientation does limit elbow extension to some degree.
The great apes (chimpanzees, gorillas, and orangutans) and the lesser apes (gibbons) move about in a much less stereotypical fashion than do monkeys. To accommodate this more varied form of limb use, the hominoid humeroulnar joint, with its deeply socketed articular surfaces and well-developed medial and lateral trochlear ridges all around the joint margins, is designed to provide maximum stability throughout the flexion-extension range. 20 - 22 The use of overhead suspensory postures and locomotion in apes has led to the evolution of the capacity for complete elbow extension. Apes even keep their elbows extended during quadrupedal locomotion. The ideal joint configuration for resistance of transarticular stress with fully extended elbows during quadrupedal postures would be to have a trochlear notch that was proximally directed. It could then act as a cradle to support the humerus during locomotion. However, a proximal orientation of the trochlear notch would severely limit elbow flexion by impingement of the coronoid process within its fossa. The anteroproximal orientation of the trochlear notch in apes thus represents a compromise that safely supports the humerus on the ulna in extended elbow positions during locomotion without unduly sacrificing elbow flexion. 1
On the lateral side of the elbow, the articular surface on the capitellum extends farther posteriorly in apes and humans than in monkeys, allowing the radius to move with the ulna into full extension of the elbow. In addition, the capitellum of apes and humans is uniformly rounded, reflecting versatility rather than stereotypy in forelimb usage ( Fig. 1-4 ).

FIGURE 1-4 Distal humeri of a baboon, a chimpanzee, and a human from the lateral aspect. The articular surface of the capitellum extends further onto the posterior surface of the bone (small arrows) in humans and chimpanzees to permit full extension at the humeroradial joint.
The gutter-like region between the trochlea and capitellum—the zona conoidea—is a relatively flat plane that terminates distally in most monkeys. In the hominoids, it continues posteriorly (see Fig. 1-1 ). 20, 21 The zona conoidea articulates with the bevel of the radial head, and differences in its configuration reflect differences in the shape of the radial head.
The radial head of hominoid primates is nearly circular, and the peripheral rim is symmetrical and beveled all around the circumference of the radial head for articulation with the zona conoidea ( Fig. 1-5 ). This configuration provides good contact to resist dislocation of the radial head from the humerus under the varied loading regimes experienced by the hominoid elbow and can stabilize the radial head in all positions of pronosupination. 20, 21

FIGURE 1-5 Diagrammatic anterior views of the right humeroradial joints of a monkey and an ape in the prone and supine positions. In the monkey, the lateral bevel of the radial head comes into maximum congruence with the zona conoidea (hatched area) in the prone position, thereby creating a maximally stable joint configuration. In the ape, the rim of the more symmetrical radial head maintains good contact with the recessed zona conoidea in all positions of pronosupination. This contributes to a configuration emphasizing universal stability at the ape elbow rather than a position of particular stability, as seen in the monkey.
(Adapted from Rose, M. D.: Another look at the anthropoid elbow. J. Hum. Evol. 17:193, 1988.)
In most monkeys and prosimians, the radial head is ovoid and the proximal radioulnar joint articulation is restricted to the anterior and medial surfaces; as a result, the joint becomes close packed for stability in pronation ( Fig. 1-6 ). In apes and humans, on the other hand, this articular surface extends almost all the way around the head, implying a greater range of pronosupination. 20 The radial notch of the ulna in most monkeys and prosimians faces either anterolaterally or directly anteriorly, whereas in hominoids, it faces more laterally. 20, 21 The configuration observed in apes and humans emphasizes a broad range of pronosupination with a nearly equal degree of stability in all positions. 20, 21

FIGURE 1-6 Diagrammatic view of the radioulnar joint in pronation and supination in a monkey and an ape. A section through the radius and ulna in the region of the radial notch is superimposed on an outline of the distal humerus. In the monkey, the radial notch faces anterolaterally, whereas in the ape, it faces more directly laterally. The radial head of the monkey with its lateral lip comes into maximum congruence in the pronated position, conferring maximum stability in this position. The ape radioulnar joint, on the other hand, displays no such position of particular stability and instead emphasizes mobility.
(Adapted from Rose, M. D.: Another look at the anthropoid elbow. J. Hum. Evol. 17:193, 1988.)
In general terms, most of the differences in elbow joint morphology between quadrupedal monkeys and the apes can be related to the development of a position of particular stability in monkeys versus more universal stability in apes.
A few additional features of the human elbow are shared with apes, such as a more distal biceps tuberosity (longer radial neck) relative to their body size. 21 In apes, this is probably related to the demands for powerful elbow flexion to raise the center of mass of the body during climbing and suspensory postures and locomotion. Although the radial tuberosity faces more or less anteriorly in most primates, it faces more medially in apes and humans, reflecting their greater range of pronosupination. 17 Extreme supination is an important component of suspensory locomotion in apes, and the medially placed tuberosity provides maximum supination torque near full supination. 14, 30 Apes and humans share a relatively short lever arm for triceps compared with that of most other primates, which is generally attributed to the demands for rapid elbow extension during suspensory locomotion. Finally, apes and humans are distinguished from other primate species in possessing a biomechanical carrying angle at the elbow. Sarmiento 22 has argued that the evolution of a carrying angle in apes is related to the need to bring the center of mass of the body beneath the supporting hand during suspensory locomotion in a manner similar to that in which the valgus knee of humans brings the foot nearer the center of mass of the body during the single limb support phase of walking ( Fig. 1-7 ).

FIGURE 1-7 Frontal view of an arm-swinging gibbon showing the skeletal structure of the forelimb. The carrying angle of the elbow brings the center of mass (i.e., center of gravity [ cg ]) more nearly directly under the supporting hand.
(Adapted from Sarmiento, E. E.: Functional Differences in the Skeleton of Wild and Captive Orang-Utans and Their Adaptive Significance. Ph.D. Thesis, New York University, 1985.)
All of these features have been retained in humans because of their continued advantages for tool use and other behaviors. Powerful flexion is clearly important. The continued importance of the carrying angle is perhaps less obvious, but one advantage that it does offer is that flexion of the elbow is accompanied by adduction of the forearm, thus bringing the hands more in front of the body, where most manipulatory activities are undertaken.
The morphology of the modern human elbow is not identical to that of the ape elbow, however. In some cases, the differences are simply a matter of degree. For example, although both apes and humans are distinguished from other primates in the medial orientation of the radial tuberosity, it is more extreme in position in the ape; in the human it is typically slightly anterior to true medial. In addition, although the olecranon is short in both humans and apes compared with most monkeys, it is slightly longer in humans than in apes and also shaped to maintain this length throughout the range of flexion—both of which are advantageous for powerful manipulatory activities. 4
Other differences between the elbow morphology of humans and that of apes can be related to the fact that the human forelimb has no role in locomotion. These differences include a less robust coronoid process and a relatively narrower, proximally oriented trochlear notch in humans, indicating relative stability in flexion rather than the need to support the weight of the body during quadrupedal locomotion in extension. 1, 13 Humans possess a smaller and more distally placed lateral epicondyle and a less well-developed supracondylar crest than is seen in the apes, reflecting diminished leverage of the wrist extensors and brachioradialis. 23 - 25 Humans have no bowing of the ulna that is related to enhancing the leverage of the forearm pronators and supinators in apes. 1 Finally, a diminution in the prominence of the trochlear ridges and steep lateral margin of the olecranon fossa in humans can be related to the overall reduction in stresses at the human elbow and the concomitant relaxation on the demands for strong stabilization in all positions. 20, 21
When exactly did the basic pattern for the hominoid elbow arise, and how old is the morphology of the modern human elbow? For answers to these questions we must turn to the fossil record.

FOSSIL EVIDENCE
Dendropithecus macinnesi, Limnopithecus legetet, and Proconsul heseloni (all from Africa) are among the earliest known hominoid species dated to the early part of the Miocene epoch (23 to 16 mya) for which postcranial material is known. Overall, the distal humeri of the first two of these forms resemble generalized New World monkeys such as Cebus (capuchin monkeys). The trochlea does not display a prominent lateral ridge, and the zona conoidea is relatively flat. The trochlear notch faces anteriorly, and the head of the radius is oval in outline with a well-developed lateral lip. These features generally are considered to be primitive for higher primates (monkeys, apes, and humans). 8, 9, 20
P. heseloni, on the other hand, does display some features characteristic of extant hominoids. It has a globular capitellum, well-developed medial and lateral trochlear ridges, and a deep zona conoidea forming the medial wall of a recessed gutter between the capitellum and trochlea. 20 In general, the elbow region of Proconsul resembles that of extant hominoids in features related to general stability and range of pronosupination; yet full pronation remained a position of particular stability. 20
The limited fossil material that is available from the late Miocene epoch (16 to 5 mya) suggests that many hominoid species, including members of the genera Dryopithecus (from Europe), Sivapithecus (from Europe and Asia), and Oreopithecus (from Europe), displayed the features characteristic of the modern hominoid elbow. Although it is possible that these features arose in parallel in different genera, the more parsimonious explanation is that they inherited this morphology from an early to middle Miocene common ancestor, possibly similar to P. heseloni . 16, 29, 31 Assuming that the characteristic features of the hominoid elbow are shared derived traits, that is, traits inherited from a single common ancestor, we can say that the elbow morphology of modern apes and humans can be dated to roughly 15 to 20 mya.
The majority of paleoanthropologists agree that humans are most closely related to the African apes (chimpanzees and gorillas) and that the two lineages arose in the late Miocene or earliest Pliocene period (between 10 and 4 mya). 8 The earliest known fossils of the human lineage (hominids) date from the early Pliocene era, approximately 4 to 5 mya. There are three genera of these earliest hominids currently recognized, Ardipithecus, Paranthropus, and Australopithecus . The latter is the best known and most widespread genus, and includes the famous “Lucy” skeleton from Hadar, Ethiopia ( A. afarensis ). 5, 12 The genus Homo , to which our own species belongs, first appeared about 2.5 to 2 mya in East Africa with its earliest member species, H. habilis .
All of the hominids from the Pliocene period were bipedal, although some probably spent significant time climbing trees. 23 - 26 28 The development of bipedalism freed the upper extremity from the requirements of locomotion, placing greater emphasis on increasing mobility. The ability to supinate and pronate was an immense advantage to hominids in caring for their young, defending themselves, and gathering food. It was also critical in efficient tool handling, which developed approximately 2 mya, at about the same time as H. habilis , although there is debate about which species of early hominid was responsible for making them. 27
Several distal humeri are known from these early hominid species. All of the early hominid distal humeri lack the steep lateral margin of the olecranon fossa that is characteristic of chimpanzees and gorillas. However, they do show a considerable amount of morphologic variation in other characteristics ( Fig. 1-8 ). On the basis of the contour of the distal end of the humeral shaft, the placement of the epicondyles, and the configuration of the articular surface, the fossil distal humeri have been divided into two groups. The first group is characterized by a weakly projecting lateral epicondyle that is placed low, at about the level of the capitellum, and by a moderately developed lateral trochlear ridge. 23, 24 These are features shared with modern humans, and consequently, this group generally is referred to as early Homo . The second group includes the Australopithecus and Paranthropus species and is characterized by a well-developed lateral epicondyle that is high relative to the capitellum. These features are similar to those of modern apes.

FIGURE 1-8 Distal humeri of Plio-Pleistocene hominids. Gombore IB 7594 represents early Homo on the basis of the moderate development of the lateral trochlear ridge and low position of the lateral epicondyle. AL 288-1m (part of the “Lucy” skeleton, Australopithecus afarensis ) displays a more prominent lateral trochlear ridge, a recessed, gutter-like zona conoidea, a high position of the lateral epicondyle, and a well-developed supracondylar crest. Therefore, it resembles living apes in many features of its elbow morphology. KNM-ER 739 has been attributed to Paranthropus boisei and, like AL 288-1m, has a lateral epicondyle that is positioned above the articular surfaces. However, it is more like Homo , with the moderate development of the lateral trochlear ridge.
A number of fragments of early hominid proximal radii have been recovered representing each of the currently recognized species. The proximal radial fragments that have been attributed to early Homo display a much narrower bevel around the capitellar fovea than that of the modern apes and the earlier hominin group. This provides for articulation with a more shallow zona conoidea and a more vertical and uniformly wide surface on the side of the head for articulation with the ulna favoring pronosupination over stability. Other primitive hominoid features include thick cortices, a relatively long and angulated radial neck (lower neck shaft angle), and a more anteromedially (rather than medially) placed biceps tuberosity. Many of these features are still present in a small percentage of modern humans, limiting the functional conclusions that can be drawn and suggesting a mosaic pattern of evolution. 18, 19
Some early hominid ulnae that have been recovered appear to retain many primitive features including a longer more curved shaft, greater mediolateral width proximally, and a nonprominent interosseous border. 1, 2, 10 However, early human ulnae attributed to the genus Homo are similar to those of modern humans in having a prominent interosseous border, a supinator crest, and a well-marked hollow for the play of the tuberosity of the radius. 6, 7, 15 It appears, therefore, that many of the characteristics that distinguish the human elbow from that of the ape can be found in the earliest members of our genus.
In overview, the combination of comparative anatomy and the fossil record indicates that the modern human elbow owes its beginnings to our hominoid ancestry. Current evidence suggests that many of the characteristic features of the human distal humerus and proximal radius and ulna can be projected back approximately 15 to 20 mya to a common ancestor of extant apes and humans. Functional analysis suggests that this morphologic structure arose in hominoid primates in response to the need for stabilization throughout the flexion-extension and pronosupination ranges of motion to permit a more versatile form of forelimb use. This morphology was still largely intact following the evolution of upright posture and bipedal locomotion in the earliest known hominids. However, as the forelimb became less and less involved in locomotion, the hominid elbow underwent additional modifications, relaxing some of the emphasis on stabilization and increasing performance throughout the range of movement. The fossil record indicates that the distinct form of the modern human elbow probably first appeared about 2 mya in our ancestor H. habilis . This morphology has changed only subtly during all subsequent stages of human evolution.

Acknowledgments
SGL would like to thank Jack Stern and John Fleagle for helpful comments on earlier versions of this chapter, and Luci Betti-Nash for the preparation of figures.
The references in this chapter which suggest the evolution of the human from a lower form are not accepted by and do not express the views of all of the contributors of this book.

References

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4 Drapeau M.S. Functional anatomy of the olecranon process in hominoids and Plio-Pleistocene hominins. Am. J. Phys. Anthropol. . 2004;124:297.
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CHAPTER 2 Anatomy of the Elbow Joint

Bernard F. Morrey
This chapter discusses the normal anatomy of the elbow region. Abnormal and surgical anatomy is addressed in subsequent chapters of this book dealing with the pertinent condition.

TOPICAL ANATOMY AND GENERAL SURVEY
The contours of the biceps muscle and antecubital fossa are easily observed anteriorly. Laterally, the avascular interval between the brachioradialis and the triceps, the so-called column, is an important palpable landmark for surgical exposures ( Fig. 2-1 ). Laterally, the tip of the olecranon, the lateral epicondyle, and the radial head also form an equilateral triangle and provide an important landmark for joint aspiration and for elbow arthro-scopy (see Chapters 37 and 77 ). The flexion crease of the elbow is in line with the medial and lateral epicondyles and thus is actually 1 to 2 cm proximal to the joint line when the elbow is extended ( Fig. 2-2 ). The inverted triangular depression on the anterior aspect of the extremity distal to the epicondyles is called the cubital (or antecubital) fossa.

FIGURE 2-1 The palpable landmarks of the tip of the olecranon and the medial and lateral epicondyles form an inverted triangle posteriorly when the elbow is flexed 90 degrees but are colinear when the elbow is fully extended.
(Redrawn from Anson, B. J., and McVay, C. B.: Surgical Anatomy, Vol. 2, 5th ed. Philadelphia, W. B. Saunders Co., 1971.)

FIGURE 2-2 A line placed over the flexion crease ( A ) is actually situated about 1 cm above the elbow joint line ( B ).
The superficial cephalic and basilic veins are the most prominent superficial major contributions of the anterior venous system and communicate by way of the median cephalic and median basilic veins to form an “M” pattern over the cubital fossa ( Fig. 2-3 ).

FIGURE 2-3 The superficial venous pattern of the anterior aspect of the elbow demonstrates a rather characteristic inverted M pattern formed by the median cephalic and median basilic veins.
(Redrawn from Anson, B. J., and McVay, C. B.: Surgical Anatomy, Vol. 2, 5th ed. Philadelphia, W. B. Saunders Co., 1971.)
The extensor forearm musculature originates from the lateral epicondyle and was termed the mobile wad by Henry. 37 This forms the lateral margin of the antecubital fossa and the lateral contour of the forearm and comprises the brachioradialis and the extensor carpi radialis longus and brevis muscles. The muscles comprising the contour of the medial anterior forearm include the pronator teres, flexor carpi radialis, palmaris longus, and flexor carpi ulnaris. Henry has demonstrated that their relationship and location can be approximated by placing the opposing thumb and the index, long, and ring fingers over the anterior medial forearm. The dorsum of the forearm is contoured by the lateral extensor musculature, consisting of the anconeus, extensor carpi ulnaris, extensor digitorum quinti, and extensor digitorum communis.
Dermal innervation about the proximal elbow is rather variable being provided by the lower lateral cutaneous (C5, C6) and medial cutaneous (radial nerve, C8, T1 and T2) nerves of the arm. The forearm skin is innervated by the medial (C8, T1), lateral (musculocutaneous, C5, C6), and posterior (radial nerve, C6-8) cutaneous nerves of the forearm ( Fig. 2-4 ).

FIGURE 2-4 Typical distribution of the cutaneous nerves of the anterior ( A ) and posterior ( B ) aspects of the upper limb.
(Redrawn from Cunningham, D. J.: In G. J. Romanes (ed.): Textbook of Anatomy, 12th ed. New York, Oxford University Press, 1981.)

OSTEOLOGY

HUMERUS
The distal humerus consists of an arch formed by two condyles that contain the articular surfaces of the trochlea and capitellum ( Fig. 2-5 ).

FIGURE 2-5 The bony landmarks of the anterior aspect of the distal humerus.
Medial to the trochlea, the prominent medial epicondyle serves as a source of attachment of the medial ulnar collateral ligament and the flexor-pronator group of muscles. Laterally, the lateral epicondyle is located just proximal to the capitellum and is much less prominent than the medial epicondyle. The lateral ulnar collateral ligament and the supinator-extensor muscle group originate from the flat, irregular surface of the lateral epicondyle.
Anteriorly, the radial and coronoid fossae accommodate the radial head and coronoid process during flexion. Posteriorly, the olecranon fossa receives the tip of the olecranon.
In about 90% of individuals, 86 a thin membrane of bone separates the olecranon and coronoid fossae ( Fig. 2-6 ). The medial supracondylar column is smaller than the lateral and explains the vulnerability of the medial column to fracture with trauma and some surgical procedures. 56 The posterior aspect of the lateral supracondylar column is flat, allowing ease of application of contoured plates (see Chapter 22 ). The prominent lateral supracondylar ridge serves as attachment for the brachioradialis and extensor carpi radialis longus muscles anteriorly and for the triceps posteriorly. It is also an important landmark for many lateral surgical approaches especially for the “column procedure” (see Chapters 7 and 32 ).

FIGURE 2-6 The prominent medial and lateral supracondylar bony columns as well as other landmarks of the posterior aspect of the distal humerus.
Proximal to the medial epicondyle, about 5 to 7 cm along the medial intramuscular septum, a supracondylar process is observed in 1% to 3% of individuals 45, 49, 81 ( Fig. 2-7 ). A fibrous band termed the ligament of Strothers may originate from this process and attach to the medial epicondyle. 38 When present, this spur serves as an anomalous insertion of the coracobrachialis muscle and an origin of the pronator teres muscle. 34 Various pathologic processes have been associated with the supracondylar process, including fracture 45 and median 4 and ulnar nerve 38 entrapment (see Chapter 80 ).

FIGURE 2-7 Typical supracondylar process located approximately 5 cm proximal to the medial epicondyle with its characteristic configuration.

RADIUS
The radial head defines the proximal radius and articulates with the capitellum. It exhibits a cylindrical shape with a depression in the midportion to accommodate the capitellum. The disc-shaped head is secured to the ulna by the annular ligament ( Fig. 2-8 ). Distal to the radial head, the bone tapers to form the radial neck, which, along with the head, is vulnerable to fracture. 83 The radial tuberosity marks the distal aspect of the neck and has two distinct parts. The anterior surface is covered by a bicipitoradial bursa protecting the biceps tendon during full pronation ( Fig. 2-9 ). However, it is the rough posterior aspect that provides the site of attachment of the biceps tendon. During full pronation the tuberosity is in a dorsal position and allows repair of a ruptured biceps tendon through a posterior approach 12 (see Chapter 34 ) and is helpful to determine axial alignment of proximal radial fractures. 26

FIGURE 2-8 Proximal aspect of the radius demonstrating the articular margin for articulation with the olecranon, the radial neck, and tuberosity.

FIGURE 2-9 A deep view of the anterior aspect of the joint revealing the submuscular bursa present about the elbow joint.

ULNA
The proximal ulna provides the greater sigmoid notch (incisura semilunaris), which serves as the major articulation of the elbow that is responsible for its inherent stability ( Fig. 2-10 ). The cortical surface of the coronoid process serves as the site of insertion of the brachialis muscle and of the oblique cord. Medially the sublime tubercle serves as insertion site of the medial ulnar collateral ligament. The triceps tendon attaches to the posterior aspect of the olecranon process.

FIGURE 2-10 A, Anterior aspect of the proximal ulna demonstrating the greater sigmoid fossa with the central groove. B, Lateral view with landmarks.
On the lateral aspect of the coronoid process, the lesser semilunar or radial notch articulates with the radial head and is oriented roughly perpendicular to the long axis of the bone. Distal to this the supinator crest serves as attachment to the supinator muscle, a tuberosity occurs on this crest, which is the site of insertion of the lateral ulnar collateral ligament. 52, 56, 66

ELBOW JOINT STRUCTURE

ARTICULATION
The elbow joint articulation is classified as a trochoginglymoid joint. 77 The ulnohumeral joint resembles a hinge (ginglymus), allowing flexion and extension. The radiohumeral and proximal radioulnar joint allows axial rotation or a pivoting (trochoid) type of motion.

Humerus
The trochlea is the hyperboloid, pulley-like surface that articulates with the semilunar notch of the ulna covered by articular cartilage through an arc of 300 degrees 42, 73, 77 ( Fig. 2-11 ). The medial contour is larger and projects more distally than does the lateral portion of the trochlea ( Fig. 2-12 ). The two surfaces are separated by a groove that courses in a helical manner from an anterolateral to a posteromedial direction.

FIGURE 2-11 Sagittal section through the elbow region, demonstrating the high degree of congruity.
(Redrawn from Anson, B. J., and McVay, C. B.: Surgical Anatomy, Vol. 2, 5th ed. Philadelphia, W. B. Saunders Co., 1971.)

FIGURE 2-12 Axial view of the distal humerus shows the isometric trochlea as well as the anterior position of the capitellum. The trochlear capitellar groove separates the trochlea from the capitellum.
The capitellum is almost spheroidal in shape and is covered with hyaline cartilage, which is about 2 mm thick anteriorly. A groove separates the capitellum from the trochlea, and the rim of the radial head articulates with this groove throughout the arc of flexion and during pronation and supination.
In the lateral plane, the orientation of the articular surface of the distal humerus is rotated anteriorly about 30 degrees with respect to the long axis of the humerus ( Fig. 2-13 ). The center of the concentric arc formed by the trochlea and capitellum is on a line that is coplanar to the anterior distal cortex of the humerus. 58 In the transverse plane, the articular surface and axis of rotation is rotated inward approximately 5 degrees ( Fig. 2-14 ), and in the frontal plane, it is tilted approximately 6 degrees in valgus 43, 47, 80 ( Fig. 2-15 ).

FIGURE 2-13 Lateral view of the humerus shows the 30-degree anterior rotation of the articular condyles with respect to the long axis of the humerus.

FIGURE 2-14 Axial view of the distal humerus demonstrates the 5- to 7-degree internal rotation of the articulation in reference to the line connecting the midportions of the epicondyles.

FIGURE 2-15 There is approximately a 6- to 8-degree valgus tilt of the distal humeral articulation with respect to the long axis of the humerus.

Proximal Radius
Hyaline cartilage covers the depression of the radial head, which has an angular arc of about 40 degrees, 77 as well as approximately 240 degrees of articular cartilage that articulates with the ulna, hence approximately 120 degrees of the radial circumference is not articular and amenable to open reduction internal fixation (ORIF) for fracture 16 ( Fig. 2-16 ). The lesser sigmoid fossa forms an arc of approximately 60 to 80 degrees, 42, 77 leaving an excursion of about 180 degrees for pronation and supination. The anterolateral third of the circumference of the radial head is void of cartilage. This part of the radial head lacks subchondral bone and thus is not as strong as the part that supports the articular cartilage; this part has been demonstrated to be the portion most often fractured. 83 The head and neck are not co-linear with the rest of the bone and form an angle of approximately 15 degrees, with the shaft of the radius directed away from the radial tuberosity 28 ( Fig. 2-17 ).

FIGURE 2-16 Hyaline cartilage covers approximately 240 degrees of the outside circumference of the radial head, allowing its articulation with the proximal ulna at the radial notch of the ulna.
(Redrawn from Langman, J., and Woerdeman, M. W.: Atlas of Medical Anatomy. Philadelphia, W. B. Saunders Co., 1976.)

FIGURE 2-17 The neck of the radius makes an angle of approximately 15 degrees with the long axis of the proximal radius.

Proximal Ulna
In most individuals, a transverse portion of non-articular cartilage divides the greater sigmoid notch into an anterior portion comprising the coronoid and the posterior olecranon ( Fig. 2-18 ).

FIGURE 2-18 The relative percentage of hyaline cartilage distribution at the proximal ulna.
(Redrawn from Tillmann, B.: A Contribution to the Function Morphology of Articular Surfaces. Translated by G. Konorza. Stuttgart, George Thieme, Publishers; P. S. G. Publishing Co., Littleton, Mass., 1978.)
In the lateral plane, the sigmoid notch forms an arc of about 190 degrees. 74 The contour is not a true hemicircle but rather is elipsoid. This explains the articular void in the midportion. 85
The orientation of the articulation is oriented approximately 30 degrees posterior to the long axis of the bone ( Fig. 2-19 ). This matches the 30 degrees anterior angulation of the distal humerus, providing stability in full extension (see Chapter 3 ). In the frontal plane, the shaft is angulated from about 1 to 6 degrees 43, 47, 73 lateral to the articulation ( Fig. 2-20 ). This angle contributes, in part, to the variation of the carrying angle, which is discussed in Chapter 3 .

FIGURE 2-19 The greater sigmoid notch opens posteriorly with respect to the long axis of the ulna. This matches the 30-degree anterior rotation of the distal humerus, as shown in Figure 2-13 .

FIGURE 2-20 There is a slight (approximately 4 degrees) valgus angulation of the shaft of the ulna with respect to the greater sigmoid notch.
The lesser sigmoid notch consists of a depression with an arc of about 70 degrees and is situated just distal to the lateral aspect of the coronoid and articulates with the radial head.

CARRYING ANGLE
The so-called carrying angle is the angle formed by the long axes of the humerus and the ulna with the elbow fully extended ( Fig. 2-21 ). In men, the mean carrying angle is 11 to 14 degrees, and in women, it is 13 to 16 degrees. 3, 43, 69 Furthermore, the carrying angle is approximately 1 degree greater in the dominant than nondominant side. 88

FIGURE 2-21 The carrying angle is formed by the variable relationship of the orientation of the humeral articulation referable to the long axis of the humerus and the valgus angular relationship of the greater sigmoid fossa referable to the long axis of the ulna.
(Redrawn from Lanz, T., and Wachsmuth, W.: Praktische Anatomie. ARM, Berlin, Springer, 1959.)

JOINT CAPSULE
The anterior capsule inserts proximally above the coronoid and radial fossae ( Fig. 2-22 ). Distally, the capsule attaches to the anterior margin of the coronoid medially as well as to the annular ligament laterally. Posteriorly, the capsule attaches just above the olecranon fossa, distally along the supracondylar bony columns. Distally, attachment is along the medial and lateral articular margin of the sigmoid notch. The greatest capacity of the elbow occurs at about 80 degrees of flexion 40, 70 and is 25 to 30 mL. 70

FIGURE 2-22 Distribution of the synovial membrane from the posterior aspect, demonstrating the presence of the synovial recess under the annular ligament and about the proximal ulna.
(Redrawn from Beethman, W. P.: Physical Examination of the Joints. Philadelphia, W. B. Saunders Co., 1965.)
The anterior capsule is normally a thin transparent structure but significant strength is provided by transverse and obliquely directed fibrous bands 23, 56 ( Fig. 2-23 ). The anterior structure is, of course, taut in extension but becomes lax in flexion. The joint capsule is innervated by highly variable branches from all major nerves crossing the joint, including the contribution from the musculoskeletal nerve ( Fig. 2-24 ).

FIGURE 2-23 There is a cruciate orientation of the fibers of the anterior capsule that provides a good deal of its strength.
(Redrawn from Langman, J., and Woerdeman, M. W.: Atlas of Medical Anatomy. Philadelphia, W. B. Saunders Co., 1978.)

FIGURE 2-24 A typical distribution of the contributions of the musculocutaneous radial median and ulnar nerves to the joint capsule.
(Redrawn from Gardner, E.: The innervation of the elbow joint. Anat. Rec. 102:161, 1948.)

LIGAMENTS
The collateral ligaments of the elbow are formed by specialized thickenings of the medial and lateral capsules.

Medial Collateral Ligament Complex
The medial collateral ligament consists of three parts: anterior, posterior, and transverse segments ( Fig. 2-25 ). The anterior bundle is the most discrete component, the posterior portion being a thickening of the posterior capsule, and is well defined only in about 90 degrees of flexion. The transverse component (ligament of Cooper) appears to contribute little or nothing to elbow stability.

FIGURE 2-25 The classic orientation of the medial collateral ligament, including the anterior and posterior bundles, and the transverse ligament. This last structure contributes relatively little to elbow stability.
The ligament originates from a broad anteroinferior surface of the epicondyle. 65 The ulnar nerve rests on the posterior aspect of the medial epicondyle but is not intimately related to the fibers of the anterior bundle of the medial collateral ligament itself. This has obvious implications with regard to the treatment of ulnar nerve decompression by medial epicondylar ostectomy. A more obliquely oriented excision might be most appropriate to both decompress the ulnar nerve and preserve the collateral ligament origin. On the lateral projection, the origin of the anterior bundle of the medial collateral ligament is precisely at the axis of rotation at the anterior, inferior margins of the medial epicondyle 62 ( Fig. 2-26 ). The posterior bundle inserts along the midportion of the medial margin of the semilunar notch. The width of the anterior bundle is approximately 4 to 5 mm compared with 5 to 6 mm at the midportion of the fan-shaped posterior segment. 56 Recently ultrasound assessment has proved helpful in further documenting the dimensions of these structures. 61

FIGURE 2-26 The origin of the medial complex is at the axis of rotation, which is located at the anterior inferior aspect of the medial epicondyle. This is the projected center of the trochlea.
The function of the ligamentous structures is discussed in detail below. Clinically and experimentally, the anterior bundle is clearly the major portion of the medial ligament complex 59 and has been divided into anterior, posterior and deep medial subcomponents. 62

Lateral Ligament Complex
Unlike the medial collateral ligament complex, with its rather consistent pattern, the lateral ligaments of the elbow joint are less discrete, and individual variation iscommon. 30, 31, 40, 75 Our investigation has suggested that several components make up the lateral ligament complex: (1) the radial collateral ligament, (2) the annular ligament, (3) a variably present accessory lateral collateral ligament, and (4) the lateral ulnar collateral ligament. These observations have now been confirmed by others. The current thinking is to consider the complex to be roughly in the shape “Y,” the arms of which attach to the anterior and posterior aspect of the semilunar notch 13, 72 ( Fig. 2-27 ).

FIGURE 2-27 Dissection demonstrating the “Y” orientation of the lateral collateral ligament complex.

Radial Collateral Ligament
This structure originates from the lateral epicondyle and is actually a complex of several components ( Fig. 2-28 ). Its superficial aspect provides a source of origin for a portion of the supinator muscle. The length averages approximately 20 mm with a width of approximately 8 mm. This portion of the ligament is almost uniformly taut throughout the normal range of flexion and extension, indicating that the origin of the ligament is very near the axis of flexion ( Fig. 2-29 ).

FIGURE 2-28 Schematic representation of the radial collateral ligament complex showing several portions, one of which, termed the radial collateral ligament, extends from the humerus to the annular ligament. This is the portion that is implicated in clinical instability.

FIGURE 2-29 The lateral collateral complex originates at the center of the lateral epicondyle.

Annular Ligament
A strong band of tissue originating and inserting on the anterior and posterior margins of the lesser sigmoid notch forms the annular ligament and maintains the radial head in contact with the ulna. The ligament is tapered distally to give the shape of a funnel and contributes about four fifths of the fibro-osseous ring. 52 The structure is not as simple as it appears because fibers arc medially and laterally to secure the annular ligament to the ulna. 72 A synovial reflection extends distal to the lower margin of the annular ligament, forming the sacciform recess. The radial head is not a pure circular disc 76 ; thus, it has been observed that the anterior insertion becomes taut during supination and the posterior aspect becomes taut during extremes of pronation. 88

Lateral Ulnar Collateral Ligament
In 1985 Morrey and An first described the so-called lateral ulnar collateral ligament. 56 Before this, however, Martin haddescribed a lateral ligament complex including “…additional fibers inserting from the tubercle of the supinator crest to the humerus.” This structure subsequently has been demonstrated to be invariably present and critically important clinically. It originates from the lateral epicondyle and blends with the fibers of the annular ligament arching superficial and distal to it. 66 The insertion is at the tubercle of the crest of the supinator on the ulna. Although the origin blends with the origin of the lateral collateral ligament complex occupying the posterior portion, the insertion is more discrete at the tubercle ( Fig. 2-30 ). The function of this ligament is to provide stability to the ulnohumeral joint and was shown to be deficient in posterolateral rotatory instability of the joint. 64, 65 As confirmed by several subsequent assessments, the key factor is that this ligament represents the primary lateral stabilizer of the elbow and is taut in flexion and extension ( Fig. 2-31 ).

FIGURE 2-30 Artist’s rendition of lateral collateral complex noting the thickening of the lateral ulnar collateral ligament with a more discrete insertion at the tubercle of the supinator. In life, the supinator origin obscures the ligament, making it unnoticeable unless the supinator muscle has been removed.
(From Pede.)

FIGURE 2-31 The lateral ulnar collateral ligament complex has an origin at the axis of rotation and thus is isometric, being taut both in extension ( A ) and in flexion ( B ). Note presence of the accessory ligament.

Accessory Lateral Collateral Ligament
This definition has been applied by Martin to the ulnar insertion of discrete fibers on the tubercle of the supinator as described previously. Others have termed this the lateral arm of the “Y” ligament. 72 Proximally, the fibers tend to blend with the inferior margin of the annular ligament (see Fig. 2-27 ). Its function is to further stabilize the annular ligament during varus stress.

Quadrate Ligament
A thin, fibrous layer covering the capsule between the inferior margin and the annular ligament and the ulna is referred to as the quadrate ligament 20, 60 or the ligament of Denucè. 76 Spinner and Kaplan have demonstrated a functional role for the structure, describing the anterior part as a stabilizer of the proximal radial ulnar joint during full supination. 76 The weaker posterior attachment stabilizes the joint in full pronation.

Oblique Cord
The oblique cord is a small and inconstant bundle of fibrous tissue formed by the fascia overlying the deep head of the supinator and extending from the lateral side of the tuberosity of the ulna to the radius just below the radial tuberosity (see Fig. 2-23 ). Although the morphologic significance is debatable 53, 76 and the structure is not considered to be of great functional consequence, 31 it has been noted to become taut in full supination, and contracture of the oblique cord has been implicated in the etiology of idiopathic limitation of forearm supination. 10 At this point, we consider this structure as a curiosity.

Bursae
The bursae were first detailed by Monro in 1788, and several bursae have been described at the elbow joint. 55 Lanz recognized seven bursae, including three associated with the triceps. 52 On the posterior aspect of the elbow, the superficial olecranon bursa, which develops around age 7 years, 18 between the olecranon process and the subcutaneous tissue is wellknown 33 ( Fig. 2-32 ). A deep subtendinous bursa is present as the triceps inserts on the tip of the olecranon. An occasional deep subtendinous bursa is likewise present between the tendon and the tip of the olecranon. A bursa has also even been described deep to the anconeus muscle in about 12% of subjects by Henle, 36 but we have not appreciated such a structure during more than 500 exposures of this region. On the medial and lateral aspects of the joint, the subcutaneous medial epicondylar bursa is frequently present, and the lateral subcutaneous epicondylar bursa occasionally has been observed. The radiohumeral bursa lies deep to the common extensor tendon, below the extensor carpi radialis brevis and superficial to the radiohumeral joint capsule. This entity has been implicated by several authors 17, 67 in the etiology of lateral epicondylitis but is probably not a major factor. The constant bicipitoradial bursa separates the biceps tendon from the tuberosity of the radius (see Fig. 2-9 ). Less commonly appreciated is the deep cubital interosseous bursa lying between the lateral aspect of the biceps tendon and the ulna, brachialis, and supinator fascia. This bursa is said to be present in about 20% of individuals. 75 The clinical significance of the relevant bursae about the elbow is detailed in Chapter 85 .

FIGURE 2-32 Posterior view of the elbow demonstrating the superficial and deep bursae that are present about this joint.

VESSELS

BRACHIAL ARTERY AND ITS BRANCHES
The cross-sectional relationship of the vessels, nerves, muscles, and bones is shown in Figure 2-33 . The brachial artery descends in the arm, crossing in front of the intramuscular septum to lie anterior to the medial aspect of the brachialis muscle. The median nerve crosses in front of and medial to the artery at this point, near the middle of the arm ( Fig. 2-34 ). The artery continues distally at the medial margin of the biceps muscle and enters the antecubital space medial to the biceps tendon and lateral to the nerve ( Fig. 2-35 ). At the level of the radial head, it gives off its terminal branches, the ulnar and radial arteries, which continue into the forearm.

FIGURE 2-33 Cross-sectional relationships of the muscles ( A ) and the neurovascular bundles ( B ). C, The region above the elbow joint. D, View taken across the elbow joint. E, View just distal to the articulation.
(Redrawn from Eycleshymer, A. C., and Schoemaker, D. M.: A Cross-Section Anatomy. New York, D. Appleton and Co., 1930.)

FIGURE 2-34 Anterior aspect of the elbow region demonstrating the intricate relationships between the muscles, nerves, and vessels.
(Redrawn from Hollinshead, W. H.: The back and limbs. In Anatomy for Surgeons, Vol. 3. New York, Harper & Row, 1969, p. 379.)

FIGURE 2-35 Illustration of the anterior extraosseous vascular anatomy demonstrating the medial arcade and the relationship of the radial recurrent artery (RR) to the proximal aspect of the radius. The inferior ulnar collateral artery (IUC) provides perforators to the supracondylar region, medial aspect of the trochlea, and medial epicondyle before it courses posteriorly to anastomose with the superior ulnar collateral (SUC) and posterior ulnar recurrent (PUR) arteries. The radial recurrent artery provides an osseous perforator to the radius as it travels proximally and posterior. B, brachial artery; R, radial artery.
(Redrawn from Yamaguchi, K., Sweet, F. A., Bindra, R., Morrey, B. F., and Gelberman, R. H.: The extraosseous and intraosseous arterial anatomy of the adult elbow. J. Bone Joint Surg. 79A:1654, 1997.)
The brachial artery usually is accompanied by medial and lateral brachial veins. Proximally, in addition to its numerous muscular and cutaneous branches, the large, deep brachial artery courses posteriorly and laterally to bifurcate into the medial and radial collateral arteries. The medial collateral artery continues posteriorly, supplying the medial head of the triceps and ultimately anastomosing with the interosseous recurrent artery at the posterior aspect of the elbow. The radial collateral artery penetrates the lateral intermuscular septum and accompanies the radial nerve into the antecubital space, where it anastomoses with the radial recurrent artery at the level of the lateral epicondyle.
The detailed vascular anatomy of the elbow region has been nicely described recently in great detail by Yamaguchi et al. 89 The major branches of the brachial artery are the superior and inferior ulnar collateral arteries, which originate medial and distal to the profunda brachial artery. The superior ulnar collateral artery is given off just distal to the midportion of the brachium, penetrates the medial intermuscular septum, and accompanies the ulnar nerve to the medial epicondyle, where it terminates by anastomosing with the posterior ulnar recurrent artery and variably with the inferior ulnar collateral artery ( Fig. 2-36 ).

FIGURE 2-36 Illustration of the posterior collateral circulation of the elbow. There are perforating vessels on the posterior aspect of the lateral epicondyle, in the olecranon fossa, and on the medial aspect of the trochlea. The tip of the olecranon is supplied by perforators from the posterior arcade in the olecranon fossa. The superior ulnar collateral artery (SUC) is seen terminating in the posterior arcade. IUC, inferior ulnar collateral artery; PUR, posterior ulnar recurrent artery; IR, interosseous recurrent artery, RR, radial recurrent artery; RC, radial collateral artery; MC, middle collateral artery.
(Redrawn from Yamaguchi, K., Sweet, F. A., Bindra, R., Morrey, B. F., and Gelberman, R. H.: The extraosseous and intraosseous arterial anatomy of the adult elbow. J. Bone Joint Surg. 79A:1655, 1997.)
The inferior ulnar collateral artery arises from the medial aspect of the brachial artery about 4 cm proximal to the medial epicondyle. It continues distally for a short course, dividing into and anastomosing with branches of the anterior ulnar recurrent artery, and it supplies a portion of the pronator teres muscle.

RADIAL ARTERY
The radial artery typically originates at the level of the radial head, emerges from the antecubital space between the brachioradialis and the pronator teres muscle, and continues down the forearm under the brachioradialis muscle. A more proximal origin occurs in up to 15% of individuals. 54 The radial recurrent artery originates laterally from the radial artery just distal to its origin. It ascends laterally on the supinator muscle to anastomose with the radial collateral artery at the level of the lateral epicondyle, to which it provides circulation. For better visualization, the radial recurrent artery sometimes is sacrificed with the anterior elbow exposure.

ULNAR ARTERY
The larger of the two terminal branches of the brachial artery is the ulnar artery. There is relatively little variation in its origin, which is usually at the level of the radial head. The artery traverses the pronator teres between its two heads and continues distally and medially behind the flexor digitorum superficialis muscle. It emerges medially to continue down the medial aspect of the forearm under the cover of the flexor carpi ulnaris. Two recurrent branches originate just distal to the origin of the ulnar artery. The anterior ulnar recurrent artery ascends deep to the humeral head of the pronator teres and deep to the medial aspect of the brachialis muscle to anastomose with the descending superior and inferior ulnar collateral arteries. The posterior ulnar recurrent artery originates with or just distal to the smaller anterior ulnar recurrent artery and passes proximal and posterior between the superficial and deep flexors posterior to the medial epicondyle. This artery continues proximally with the ulnar nerve under the flexor carpi ulnaris to anastomose with the superior ulnar collateral artery. Additional extensive communication with the inferior ulnar and middle collateral branches constitutes the rete articulare cubiti (see Fig. 2-35 ).
The common interosseous artery is a large vessel originating 2.5 cm distal to the origin of the ulnar artery. It passes posteriorly and distally between the flexor pollicis longus and the flexor digitorum profundus just distal to the oblique cord, dividing into anterior and posterior interosseous branches. The interosseous recurrent artery originates from the posterior interosseous branch. This artery runs proximally through the supinator muscle to anastomose with the vascular network of the olecranon (see Fig. 2-36 ).

NERVES
Specific clinical and pertinent anatomic aspects of the nerves in the region of the elbow are discussed in subsequent chapters as appropriate. A general survey of the common anatomic patterns is given here (see Fig. 2-33 ).

MUSCULOCUTANEOUS NERVE
The musculocutaneous nerve originates from C5-8 nerve roots and is a continuation of the lateral cord. It innervates the major elbow flexors, the biceps and brachialis, and continues through the brachial fascia lateral to the biceps tendon, terminating as the lateral antebrachial cutaneous nerve ( Fig. 2-37 ). The motor branch enters the biceps and the brachialis approximately 15 and 20 cm below the tip of the acromion, respectively. 48

FIGURE 2-37 The musculocutaneous nerve innervates the flexors of the elbow and continues distal to the joint as the lateral cutaneous nerve of the forearm.
(Redrawn from Langman, J., and Woerdeman, M. W.: Atlas of Medical Anatomy. Philadelphia, W. B. Saunders Co., 1976.)

MEDIAN NERVE
Arising from the C5-8 and T1 nerve roots, the median nerve enters the anterior aspect of the brachium, crossing in front of the brachial artery as it passes across the intermuscular septum. It follows a straight course into the medial aspect of the antecubital fossa, medial to the biceps tendon and the brachial artery. It then passes under the bicipital aponeurosis. The first motor branch is provided to the pronator teres, through which it passes. 2, 39 It enters the forearm and continues distally under the flexor digitorum superficialis within the fascial sheath of this muscle.
There are no branches of the median nerve in the arm ( Fig. 2-38 ). In the cubital fossa, a few small articular branches are given off before the motor branches to the pronator teres, the flexor carpi radialis, the palmaris longus, and the flexor digitorum superficialis. Because all branches arise medially, medial retraction of the nerve during exposure of the anterior aspect of the elbow is a safe technique.

FIGURE 2-38 The median nerve innervates the flexor pronator group of muscles about the elbow, but there are no branches above the joint.
(Redrawn from Langman, J., and Woerdeman, M. W.: Atlas of Medical Anatomy. Philadelphia, W. B. Saunders Co., 1976.)
The anterior interosseous nerve innervates the flexor pollicis longus and the lateral portion of the flexor digitorum profundus. It arises from the median nerve near the inferior border of the pronator teres and travels along the anterior aspect of the interosseous membrane in the company of the anterior interosseous artery.

RADIAL NERVE
The radial nerve is a continuation of the posterior cord and originates from the C6, C7, and C8 nerve roots withvariable contributions of the C5 and T1 roots. In the midportion of the arm, the nerve courses laterally just distal to the deltoid insertion to occupy the spiral groove in the humerus that bears its name. Before entering the anterior aspect of the arm, it gives off motor branches to the medial and lateral head of the triceps, accompanied by the deep branch of the brachial artery. It then emerges inferiorly and laterally to penetrate the lateral intermuscular septum. The nerve is at risk for injury from surgery or fracture at this site. Two recent studies have placed the position of the radial nerve as 54% of the acromion/ulnar distance 22 or 1.7% of the transcondylar distance. 41 After penetrating the lateral intermuscular septum in the distal third of the arm, it descends anterior to the lateral epicondyle behind the brachioradialis. It innervates the brachioradialis with a single branch to this muscle. In the antecubital space, the nerve divides into the superficial and deep branches. The superficial branch is a continuation of the radial nerve and extends into the forearm to innervate the mid-dorsal cutaneous aspect of the forearm ( Fig. 2-39 ).

FIGURE 2-39 The muscles innervated by the right radial nerve.
(Redrawn from Langman, J., and Woerdeman, M. W.: Atlas of Medical Anatomy. Philadelphia, W. B. Saunders Co., 1976.)
The motor branches of the radial nerve are given off to the triceps above the spiral groove except for the branch to the medial head of the triceps, which originates at the entry to the spiral groove. This branch continues distally through the medial head to terminate as a muscular branch to the anconeus. This accounts for the variability of the anconeus when rotated or reflected from its origin. 11, 44, 68
In the antecubital space, the recurrent radial nerve curves around the posterolateral aspect of the radius, passing deep to the supinator muscle, which it innervates. During its course through the supinator muscle, the nerve lies over a bare area, which is distal to and opposite to the radial tuberosity. 23 The nerve is believed to be at risk at this site with fractures of the proximal radius. 79 It emerges from the muscle as the posterior interosseous nerve, and the recurrent branch innervates the extensor digitorum minimi, the extensor carpi ulnaris, and occasionally, the anconeus. The posterior interosseous nerve is accompanied by the posterior interosseous artery and sends further muscle branches distally to supply the abductor pollicis longus, the extensor pollicis longus, the extensor pollicis brevis, and the extensor indicis on the dorsum of the forearm. The nerve is subject to compression as it passes through the supinator muscle 15 or from synovial proliferation. 25, 28 Compression and entrapment problems are described in detail in Chapter 81 .

ULNAR NERVE
The ulnar nerve is derived from the medial cord of the brachial plexus from roots C8 and T1. In the midarm, it passes posteriorly through the medial intermuscular septum and continues distally anterior to the septum and under the medial margin of the triceps. It is accompanied by the superior ulnar collateral branch of the brachial artery and the ulnar collateral branch of the radial artery. Although supposedly there are no branches of this nerve in the brachium, an occasional motor branch to the triceps is encountered ( Fig. 2-40 ). The ulnar nerve passes into the cubital tunnel under the medial epicondyle and rests against the posterior portion of the medial collateral ligament, where a groove in the ligament accommodates this structure. The roof of the cubital tunnel recently has been defined and termed the cubital tunnel retinaculum. 64 Retinacular absence accounts for congenital subluxation of the ulnar nerve. Furthermore, the structure flattens with elbow flexion, thus decreasing the capacity of the cubital tunnel ( Fig. 2-41 ). 64 This accounts for the clinical observation of ulnar nerve paresthesia with elbow flexion. Similarly, elbow instability can cause traction injury to the nerve. 51

FIGURE 2-40 Muscles innervated by the right ulnar nerve. There are no muscular branches of this nerve above the elbow joint.
(Redrawn from Langman, J., and Woerdeman, M. W.: Atlas of Medical Anatomy. Philadelphia, W. B. Saunders Co., 1976.)

FIGURE 2-41 With flexion the cubital tunnel flattens, compressing the ulnar nerve ( A and B ).
(Redrawn from O’Driscoll, S. W., Horii, E., Carmichael, S. W., and Morrey, B. F.: The cubital tunnel and ulnar neuropathy. J. Bone Joint Surg. 73B:613, 1991.)
A few small capsular twigs are given to the elbow joint in this region. 8 As the nerve enters the forearm between the two heads of the flexor carpi ulnaris, it gives off a single nerve to the ulnar origin of the pronator and one to the epicondylar head of the flexor carpi ulnaris. Distally, the nerve sends a motor branch to the ulnar half of the flexor digitorum profundus. Two cutaneous nerves arise from the ulnar nerve in the distal half of the forearm and innervate the skin of the wrist and the ulnar two digits of the hand.

MUSCLES
Relevant features of the origin, insertion, and function of the muscles of the elbow region are covered in other chapters dealing with surgical exposure, functional examination, and biomechanics. This information also is discussed in various chapters when dealing with specific pathology. The following description will serve as a basic overview.

ELBOW FLEXORS

Biceps
The biceps covers the brachialis muscle in the distal arm and passes into the cubital fossa as the biceps tendon, which attaches to the posterior aspect of the radial tuberosity ( Fig. 2-42 ). The constant bicipitoradial bursa separates the tendon from the anterior aspect of the tuberosity, and the cubital bursa has been described as separating the tendon from the ulna and the muscles covering the radius (see Fig. 2-9 ). The bicipital aponeurosis, or lacertus fibrosus, is a broad, thin band of tissue that is a continuation of the anterior medial and distal muscle fasciae. It runs obliquely to cover the median nerve and brachial artery and inserts into the deep fasciae of the forearm and possibly into the ulna as well. 19

FIGURE 2-42 Anterior aspect of the arm and elbow region demonstrating the major flexors of the joint, the brachialis, and the biceps muscles.
(Redrawn from Langman, J., and Woerdeman, M. W.: Atlas of Medical Anatomy. Philadelphia, W. B. Saunders Co., 1976.)
The biceps is a major flexor of the elbow that has a large cross-sectional area but an intermediate mechanical advantage because it passes relatively close to the axis of rotation. In the pronated position, the biceps is a strong supinator. 6 The distal insertion may undergo spontaneous rupture, 57, 78 and this condition is discussed in detail later ( Chapter 34 ).

Brachialis
This muscle has the largest cross-sectional area of any of the elbow flexors but suffers from a poor mechanical advantage because it crosses so close to the axis of rotation. The origin consists of the entire anterior distal half of the humerus, and it extends medially and laterally to the respective intermuscular septa ( Fig. 2-43 ). The muscle crosses the anterior capsule, with some fibers inserting into the capsule that are said to help retract the capsule during elbow flexion. The major attachment is to the coronoid process about 2 mm distal from its articular margin. More than 95% of the cross-sectional area is muscle tissue at the elbow joint, 50 a relationship that may account for the high incidence of trauma to this muscle and the development of myositis ossificans with elbow dislocation. 84

FIGURE 2-43 Anterior humeral origin and insertion of muscles that control flexion of the elbow joint.
The muscle is innervated by the musculocutaneous nerve. The lateral portion of the muscle covers the radial nerve as it spirals around the distal humerus. The median nerve and brachial artery are superficial to the brachialis and lie behind the biceps in the distal humerus.

Brachioradialis
The brachioradialis has a lengthy origin along the lateral supracondylar bony column that extends proximally to the level of the junction of the mid and distal humerus (see Fig. 2-43 ). The origin separates the lateral head of the triceps and the brachialis muscle. The lateral border of the cubital fossa is formed by this muscle, which crosses the elbow joint with the greatest mechanical advantage of any elbow flexor. It progresses distally to insert into the base of the radial styloid ( Figs. 2-44 and 2-45 ). The muscle protects and is innervated by the radial nerve (C5, C6) as it emerges from the spiral groove. Its major function is elbow flexion. Rarely, the muscle may be ruptured. 35

FIGURE 2-44 The musculature of the posterolateral aspect of the right forearm.
(Redrawn from Langman, J., and Woerdeman, M. W.: Atlas of Medical Anatomy. Philadelphia, W. B. Saunders Co., 1976.)

FIGURE 2-45 Posterior view of the radius and ulna demonstrating the insertion of the extensors of the elbow as well as the origin of the forearm musculature.

Extensor Carpi Radialis Longus
The extensor carpi radialis longus originates from the supracondylar bony column joint just below the origin of the brachioradialis (see Fig. 2-44 ). The origin of this muscle is identified as the first fleshy fibers observed proximal to the common extensor tendon. As it continues into the midportion of the dorsum of the forearm, it becomes largely tendinous and inserts into the dorsal base of the second metacarpal. Innervated by the radial nerve (C6, C7), the motor branches arise just distal to those of the brachioradialis muscle.
In addition to wrist extension, its orientation suggests that this muscle might function as an elbow flexor.
Clinically, the origin of this muscle and its relationship with that of the extensor carpi radialis brevis have been implicated in the pathologic anatomy of tennis elbow by Nirschl ( Chapter 44 ).

Extensor Carpi Radialis Brevis
The extensor carpi radialis brevis originates from the lateral superior aspect of the lateral epicondyle (see Fig. 2-43 ). Its origin is the most lateral of the extensor group and is covered by the extensor carpi radialis longus. This relationship is important as the most commonly implicated site of lateral epicondylitis. The extensor digitorum communis originates from the common extensor tendon and is just medial or ulnar to the extensor carpi radialis brevis. At its humeral origin, the fibers of the extensor digitorum communis and brevis are grossly and histologically indistinguishable from one another 32 (see Fig. 2-44 ). The longus and brevis shares the same extensor compartment as they cross the wrist under the extensor retinaculum. The brevis inserts into the dorsal base of the third metacarpal. The function of the extensor carpi radialis brevis is pure wrist extension, with little or no radial or ulnar deviation. 1 The extensor carpi radialis brevis is innervated by fibers of the sixth and seventh cervical nerves. The motor branch arises from the radial nerve in the region of its division into deep and superficial branches.

Extensor Digitorum Communis
Originating from the anterior distal aspect of the lateral epicondyle, the extensor digitorum communis accounts for most of the contour of the extensor surface of the forearm (see Fig. 2-44 ). The muscle extends and abducts the fingers. According to Wright, the muscle can assist in elbow flexion when the forearm is pronated. This observation is not, however, supported by our cross-sectional studies. 1 Innervation is from the deep branch of the radial nerve, with contributions from the sixth through eighth cervical nerves.

Extensor Carpi Ulnaris
The extensor carpi ulnaris originates from two heads, one above and the other below the elbow joint. The humeral origin is the most medial of the common extensor group ( Fig. 2-46 ) (see also Fig. 2-43 ). The ulnar attachment is along the aponeurosis of the anconeus and at the superior border of this muscle. It is a valuable landmark for exposures of the lateral elbow joint. The insertion is on the dorsal base of the fifth metacarpal after crossing the wrist in its own compartment under the extensor retinaculum. The extensor carpi ulnaris is a wrist extensor and ulnar deviator. Fibers of the sixth through eighth cervical nerve routes innervate the muscle from branches of the deep radial nerve.

FIGURE 2-46 The extensor aspect of the forearm demonstrating the deep muscle layer after the extensor digitorum and extensor digiti minimi have been removed.
(Redrawn from Langman, J., and Woerdeman, M. W.: Atlas of Medical Anatomy. Philadelphia, W. B. Saunders Co., 1976.)

Supinator
This flat muscle is characterized by the virtual absence of tendinous tissue and a complex origin and insertion. It originates from three sites above and below the elbow joint: (1) the lateral anterior aspect of the lateral epicondyle; (2) the lateral collateral ligament; and (3) the proximal anterior crest of the ulna along the crista supinatoris. The form of the muscle is approximately that of a rhomboid, because it runs obliquely, distally, and radially to wrap around and insert diffusely on the proximal radius, beginning lateral and proximal to the radial tuberosity and continuing distal to the insertion of the pronator teres at the junction of the proximal and middle third of the radius (see Fig. 2-46 ). It is important to note that the radial nerve passes through the supinator to gain access to the extensor surface of the forearm. This anatomic feature is clinically significant with regard to exposure of the lateral aspect of the elbow joint and the proximal radius and in certain entrapment syndromes. 76
The muscle obviously supinates the forearm but is a weaker supinator than the biceps. 38 Unlike the biceps, however, the effectiveness of the supinator is not altered by the position of elbow flexion. The innervation is derived from the muscular branch given off by the radial nerve just before and during its course through the muscle with nerve fibers derived primarily from the sixth cervical root.

ELBOW EXTENSORS

Triceps Brachii
The entire posterior musculature of the arm is composed of the triceps brachii (see Fig. 2-39 ). The long head has a discrete origin from the infraglenoid tuberosity of the scapula. The lateral head originates in a linear fashion from the proximal lateral intramuscular septum on the posterior surface of the humerus. The medial head originates from the entire distal half of the posteromedial surface of the humerus bounded laterally by the radial groove and medially by the intramuscular septum. Thus, each head originates distal to the other, with progressively larger areas of origin. The long and lateral heads are superficial to the deep medial head, blending in the midline of the humerus to form a common muscle that then tapers into the triceps tendon and attaches to the tip of the olecranon with Sharpey’s fibers. 14 The tendon usually is separated from the olecranon by the subtendinous olecranon bursa. The distal 40% of the triceps mechanism consists of a layer of fascia that blends with the triceps distally.
Innervated by the radial nerve, the long and lateral heads are supplied by branches that arise proximal to the entrance of the radial nerve into the groove. The medial head is innervated distal to the groove with a branch that enters proximally and passes through the entire medial head to terminate by innervating the anconeus, an anatomic feature of considerable importance when considering some approaches (e.g., Kocher, Bryan-Morrey, Boyd, and Pankovitch) to the joint.
The function of the triceps is to extend the elbow. Lesions of the nerve in the midportion of the humerus usually do not prevent triceps function that is provided by the more proximally innervated lateral and long heads.

Subanconeus Muscle
The attachment of some muscle fibers of the medial head of the triceps to the posteromedial capsule has been termed the subanconeus muscle. This may have some functional relevance of stabilizing the fat pad to help cushion the elbow as it comes into full extension. 87

Anconeus
This muscle has little tendinous tissue because it originates from a rather broad site on the posterior aspect of the lateral epicondyle and from the lateral triceps fascia and inserts into the lateral dorsal surface of the proximal ulna (see Fig. 2-46 ). It is innervated by the terminal branch of the nerve to the medial head of the triceps. Curiously, the function of this muscle has been the subject of considerable speculation. Possibly the most accurate description of function is that proposed by Basmajian and Griffin and by DaHora, who suggest that its primary role is that of a joint stabilizer. 5, 21 The muscle covers the lateral portion of the annular ligament and the radial head. For the surgeon, the major significance of this muscle is its position as a key landmark in various lateral and posterolateral exposures and is emerging for usefulness reconstruction of the lateral elbow.

FLEXOR PRONATOR MUSCLE GROUP

Pronator Teres
This is the most proximal of the flexor pronator group. There are two heads of origin: The largest arises from the anterosuperior aspect of the medial epicondyle and the second from the coronoid process of the ulna, an attachment absent in about 10% of individuals 39 (see Fig. 2-37 ). The two origins of the pronator muscle provide an arch through which the median nerve passes to gain access to the forearm. This anatomic characteristic is a significant feature in the etiology of the median nerve entrapment syndrome and is discussed in detail in Chapter 80 . The common muscle belly proceeds radially and distally under the brachioradialis, inserting at the junction of the proximal and middle portions of the radius by a discrete broad tendinous insertion into a tuberosity on the lateral aspect of the bone. Obviously, a strong pronator of the forearm, it also is considered a weak flexor of the elbow joint. 1, 7, 82 The muscle usually is innervated by two motor branches from the median nerve before the nerve leaves the cubital fossa.

Flexor Carpi Radialis
The flexor carpi radialis originates just inferior to the origin of the pronator teres and the common flexor tendon at the anteroinferior aspect of the medial epicondyle (see Fig. 2-43 ). It continues distally and radially to the wrist, where it can be easily palpated before it inserts into the base of the second and sometimes the third metacarpal. Proximally, the muscle belly partially covers the pronator teres and palmaris longus muscles and shares a common origin from the intermuscular septum, which it shares with these muscles. The innervation is from one or two twigs of the median nerve (C6, C7), and its chief function is as a wrist flexor. At the elbow no significant flexion moment is present. 1, 24

Palmaris Longus
This muscle, when present, arises from the medial epicondyle, and from the septa it shares with the flexor carpi radialis and flexor carpi ulnaris (see Fig. 2-43 ). It becomes tendinous in the proximal portion of the forearm and inserts into and becomes continuous with the palmar aponeurosis. It is absent approximately in 10% of extremities. 71 Its major function is as a donor tendon for reconstructive surgery, and it is innervated by a branch of the median nerve.

Flexor Carpi Ulnaris
The flexor carpi ulnaris is the most posterior of the common flexor tendons originating from the medial epicondyle (see Figs. 2-38 and 2-43 ). A second and larger source of origin is from the medial border of the coronoid and the proximal medial aspect of the ulna. The ulnar nerve enters and innervates (T7-8 and T1) the muscle between these two sites of origin with two or three motor branches given off just after the nerve has entered the muscle. These are the first motor branches of the ulnar nerve, and therefore, they are useful in localizing the level of an ulnar nerve lesion. The muscle continues distally to insert into the pisiform, where the tendon is easily palpable, because it serves as a wrist flexor and ulnar deviator. With an origin posterior to the axis of rotation, weak elbow extension also may be provided by the flexor carpi ulnaris. 1

Flexor Digitorum Superficialis
This muscle is deep to those originating from the common flexor tendon but superficial to the flexor digitorum profundus; thus, it is considered the intermediate muscle layer. This broad muscle has a complex origin ( Fig. 2-47 ). Medially, it arises from the medial epicondyle by way of the common flexor tendon and possibly from the ulnar collateral ligament and the medial aspect of the coronoid. 38 The lateral head is smaller and thinner and arises from the proximal two thirds of the radius. The unique origin of the muscle forms a fibrous margin under which the median nerve and the ulnar artery emerge as they exit from the cubital fossa. The muscle is innervated by the median nerve (C7, C8, T1) with branches that originate before the median nerve enters the pronator teres. The action of the flexor digitorum superficialis is flexion of the proximal interphalangeal joints.

FIGURE 2-47 The flexor digitorum superficialis is demonstrated after the palmaris longus and flexor carpi radialis has been removed. The pronator teres has been transected and reflected. The important relationships of the nerves and arteries should be noted.
(Redrawn from Langman, J., and Woerdeman, M. W.: Atlas of Medical Anatomy. Philadelphia, W. B. Saunders Co., 1976.)

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CHAPTER 3 Biomechanics of the Elbow

Kai-Nan An, Mark E. Zobitz, Bernard F. Morrey

INTRODUCTION
Upper extremity use depends largely on a functional elbow joint. A complex joint, the elbow serves as a link in the lever arm system that positions the hand, as a fulcrum of the forearm lever, and as a load-carrying joint. Mobility and stability of the elbow joint are necessary for daily, recreational, and professional activities. Loss of function in the elbow, possibly more than that in any other joint, can jeopardize individual independence.
In our practice, a working knowledge of biomechanics has been extremely important and rewarding. Clinical relevance includes elbow joint design and technique, the rationale and execution of trauma management, and ligament reconstruction. In short, a clear understanding of biomechanics provides a scientific basis for clinical practice. 5
From the clinician’s perspective, we have found the topic of elbow mechanics best discussed according to motion (kinematics), stability (constants), and strength (force transmission).

KINEMATICS
The elbow is described as a trochoginglymoid joint. That is, it possesses 2 degrees of freedom (motion): flexion-extension and supination-pronation. The articular components include the trochlea and capitellum on the medial and lateral aspects of the bifurcated distal humerus, and distally the upper end of the ulna and the head of the radius. Thus, the joint is composed of three articulations: the radiohumeral, the ulnohumeral, and the radioulnar.

FLEXION-EXTENSION
Because of the congruity at the ulnohumeral articulation and surrounding soft tissue constraint, elbow joint motion is considered primarily a hinge type. Yet, two separate three-dimensional studies of passive motion at the elbow revealed that the elbow does not function as a simple hinge joint. 51, 69 The position of the axis of elbow flexion, as measured from the intersection of the instantaneous axis with the sagittal plane, follows an irregular course. A type of helical motion of the flexion axis has been demonstrated. 69 This pattern was previously suggested 26, 50, 61 and was attributed to the obliquity of the trochlear groove along which the ulna moves. 52 An electromagnetic tracking device that allows a three-dimensional measurement of simulated active elbow joint motion reveals the amount of potential varus-valgus and axial laxity that occurs during elbow flexion to average about 3 to 4 degrees. This has been confirmed with more advanced electromagnetic tracking technology. 101

CENTER OF ROTATION
The axis of motion in flexion and extension has been the subject of many investigations. 60 Fischer (1909), using Reuleaux’s technique, found the so-called locus of the instant center of rotation to be an area 2 to 3 mm in diameter at the center of the trochlea ( Fig. 3-1 ). 34 Subsequent experiments with the same technique described a much larger locus. 32 In a three-dimensional study of passive motion of the elbow joint, the observations of Fischer were confirmed by using the biplanar x-ray technique. 69 Based on direct experimental study as well as analytic investigation, Youm and associates 109 concluded that the axis does not change during flexion-extension. In our study, however, variations of up to 8 degrees in the position of the screw axis from individual to individual have been shown. As seen from below, the axis of rotation is internally rotated 3 to 8 degrees relative to the plane of the epicondyles. In the coronal plane, a line perpendicular to the axis of rotation forms a proximally and laterally opening angle of 4 to 8 degrees with the long axis of the humerus. 105 These data, coupled with the clinical information regarding implant loosening, have inspired the development of less constrained but coupled elbow joint replacement designs. It recently has been demonstrated that these designs do function as semiconstrained implants and allow for the normal out-of-plane rotations noted earlier (see Chapter 49 ). 75

FIGURE 3-1 Configuration and dimensions of the locus of the instant center of rotation of the elbow. This axis runs through the center of the articular surface, as viewed on both the anteroposterior (AP) and the lateral planes.
From a practical point of view, despite the different findings of various investigators, the deviation of the center of joint rotation is minimal and the reported variation is probably due to limitations in the experimental design. Thus, the ulnohumeral joint could be assumed to move as a uniaxial articulation except at the extremes of flexion and extension. The axis of rotation passes through the center of the arcs formed by the trochlear sulcus and capitellum. 56
The center of rotation can be identified from external landmarks. In the sagittal plane, the axis lies anterior to the midline of the humerus 92 and lies on a line that is colinear with the anterior cortex of the distal humerus. 69 The coronal orientation is defined by the plane of the posterior cortex of the distal humerus. 19 This axis emerges from the center of the projected center of the capitellum and from the anteroinferior aspect of the medial epicondyle (see Fig. 3-1 ).
Similarly, the effect of altering the center of rotation on the kinematics of the forearm has been recently studied. Alterations of as much as 5 mm proximally, distally, anteriorly, or posteriorly have been shown to have only a slight effect on elbow kinematics ( Fig. 3-2 ). This observation has great clinical relevance regarding the design and insertion of prosthetic replacement and articulating external fixation devices.

FIGURE 3-2 Experimental data using the electromagnetic tracking system reveals 5-mm changes in the elbow axis site ( A ) and causes relatively small effects in the kinematics of the forearm ( B ).

FOREARM ROTATION
The radiohumeral joint, which forms the lateral half of the elbow joint, has a common transverse axis with the elbow joint, which coincides with the ulnohumeral axis during flexion-extension motion. In addition, the radius rotates around the ulna, allowing for forearm rotation or supination-pronation. In general, the longitudinal axis of the forearm is considered to pass through the convex head of the radius in the proximal radioulnar joint and through the convex articular surface of the ulna at the distal radioulnar joint. 34, 97 The axis therefore is oblique to the longitudinal axes of both the radius and the ulna ( Fig. 3-3 ), and rotation is independent of elbow position. 45

FIGURE 3-3 The longitudinal axis of pronation-supination runs proximally from the distal end of the ulna to the center of the radial head. The axis is at the ulnar cortex in the distal one third of the forearm.
Mori has characterized the axis of forearm rotation as passing through the attachment of the interosseous membrane at the ulna in the distal fourth of the forearm (see Fig. 3-32 ). 62 This may have particular applications with regard to the sensitivity of forearm rotation to angular deformity in this particular portion of the bone. Clinically and experimentally, less than 10% angulation of either the radius or the ulna causes no functionally significant loss of forearm rotation. 91

FIGURE 3-32 A, Pressure distribution on elbow joint surface as external load P is applied at the distal end of the ulna. Distribution of muscle force, F e and F f , influences the magnitude, R, and the direction, F, of resultant force on the elbow joint. F represents the “attempted displacement,” U, of the humerus relative to the direction of the ulna. B, For the given loading condition, resultant joint force increased with increasing involvement of extensor muscle, as represented by the ratio of extension force F e to flexor force F f (top). Peak articular pressure and the direction of the attempted displacement of the humerus also are affected by the level of involvement of extensor muscle (bottom).
(From An, K. N., Himeno, S., Tsumura, H., Kawai, T., and Chao, E. Y.: Pressure distribution on articular surfaces: Application to joint stability evaluation. J. Biomech. 23:1013, 1990.)
In the past, ulnar rotation was described as being coupled with forearm rotation. 106 This observation could not be reproduced in a subsequent study by Youm and associates. 108 By using a metal rod introduced transversely into the ulna, extension, lateral rotation, and then flexion of the ulna was described with rotation from pronation to supination. The axial rotational movements of the ulna were also observed by others. 14, 22, 30, 43, 69, 88, 108
Ray and associates 88 also suggested that varus-valgus movement of the ulna occurs if the forearm rotates on an axis extending from the head of the radius to the index finger. Experiments from our laboratory 76 have demonstrated external axial rotation of the ulna with forearm supination. Internal rotation or closure of the lateral ulnohumeral joint occurs with pronation.
Finally, the radius has been shown to migrate 1 to 2 mm proximally with pronation. 67 This observation had not been reported previously but has been confirmed by observations at the wrist. 82

CARRYING ANGLE
The carrying angle is defined as that formed by the long axis of the humerus and the long axis of the ulna. It averages 10 to 15 degrees in men and is about 5 degrees greater in women. 1, 18, 53, 97
However, uncertainty has arisen over the use of the term carrying angle in the dynamic setting. Dempster 27 described an oscillatory pattern during elbow flexion, whereas Morrey and Chao 69 reported a linear change, with the valgus angle being the greatest at full extension and diminishing during flexion. The confusion arises because three descriptions based on different reference systems have been adopted for the measurement of carrying angle changes.


Definition 1
The carrying angle is the acute angle formed by the long axis of the humerus as the long axis of the ulna projects on the plane containing the humerus ( Fig. 3-4A ).

FIGURE 3-4 A, Carrying angle between the humerus and the ulna as measured by viewing from the direction perpendicular to the plane containing the humeral and the flexion axes. Conventionally, the acute angle instead of the obtuse angle shown is used as the carrying angle measurement. B, Carrying angle between humerus and ulna as measured by viewing from the direction perpendicular to the plane containing the ulnar and flexion axes. Conventionally, the acute angle instead of the obtuse angle shown is based as the carrying angle measurement.
(From An, K. N., Morrey, B. F., and Chao, E. Y. S.: Carrying angle of the human elbow joint. J. Orthop. Res. 1:369, 1984.)

Definition 2
The carrying angle is described as the acute angle formed by the long axis of the ulna and the projection of the long axis of the humerus onto the plane of the ulna (see Fig. 3-4B ).

Definition 3
The carrying angle is defined analytically as the abduction-adduction angle of the ulna with respect to the humerus when eulerian angles are being used to describe arm motion.
From an anatomic point of view, it is not difficult to conclude that the existence of the carrying angle is due to the existence of obliquities, or cubital angles, between the proximal humeral shaft, the trochlea, and the distal ulnar shaft. By assuming that the ulnohumeral joint is a pure hinge joint and that the axis of rotation coincides with the axis of the trochlea, the change in the carrying angle during flexion can be defined as a function of anatomic variations of the obliquity of the articulations according to simple trigonometric calculations. 8 If the first or second definition is accepted, the carrying angle changes minimally during flexion. The specific varus/valgus relationship of the forearm to the humerus during flexion therefore depends on the relative angular relationship of the humeral and ulnar articulations ( Fig. 3-5 ).

FIGURE 3-5 The positional relationship of the forearm referable to the humerus in the frontal plane of the humerus (carrying angle) is dependent on the relative tilt of the humeral and ulnar articulations referable to their long axes.

RESTRICTION OF MOTION
In normal circumstances, elbow flexion ranges from 0 degrees or slightly hyperextended to about 150 degrees in flexion. Forearm rotation averages from about 75 degrees (pronation) to 85 degrees (supination) (see Chapter 2 ). The cartilage of the trochlea forms an arc of about 320 degrees, whereas the sigmoid notch creates an arc of about 180 degrees. Generally, the arc of the radial head depression is about 40 degrees, 97 which articulates with the capitellum, presenting an angle of 180 degrees.
The significance of the 30-degree anterior angulation of the trochlea with the 30-degree posterior orientation of the greater sigmoid notch to flexion and extension and stability of the elbow joint is discussed in detail in Chapter 1 ( Fig. 3-6 ). Impact of the olecranon process on the olecranon fossa and the tension of the anterior ligament and the flexor muscles as well as tautness of the anterior bundle of the medial collateral ligament have been described as serving as a check to extension. 40, 52 The anterior muscle bulk of the arm and forearm, along with contraction of the triceps, is also reported to prevent active flexion beyond 145 degrees. 52 However, the factors limiting passive flexion include the impact of the head of the radius against the radial fossa, the impact of the coronoid process against the coronoid fossa, and tension from the capsule and triceps.

FIGURE 3-6 The distal humeral forward flexion is complemented by a 30-degree posterior rotation of the opening of the greater sigmoid notch.
(With permission, Mayo Foundation.)
For pronation and supination, Braune and Flugel 20 found that passive resistance of the stretched antagonistmuscle restricts the excursion range more than that of the ligamentous structures. Spinner and Kaplan, 96 however, have shown that the quadrate ligament does provide some static constraint to forearm rotation. Impingement of tissue restrains pronation, especially by the flexor pollicis longus, which is forced against the deep finger flexors. The entire range of active excursion in an intact arm is about 150 degrees, whereas when the muscles are removed from a cadaver specimen, the range increases to 185 to 190 degrees. With cutting the ligaments, the range increased up to 205 to 210 degrees.

CAPACITY AND CONTACT AREA OF THE ELBOW JOINT
The capacity of the elbow joint recently has been shown to average about 25 mL. The maximum capacity is observed to occur with the elbow at about 80 degrees of flexion. 78 This explains the clinical observation that stiff elbows tend to have fixed deformities at about 80 to 90 degrees of flexion. 63
Accurate measurement of the contact points of the elbow is extremely difficult, and several techniques have been applied to this highly congruous joint. 99 Silicone casting, Fuji Prescale film, and reversible cartilage staining are most commonly used. Each has advantages and disadvantages. The contact area of the articular surface during elbow joint motion has been investigated by Goodfellow and Bullough, using a staining technique. 39 They found that the central depression of the radial head articulates with the dome of the capitellum and that the medial triangular facet was always in contact with the ulna. The upper rim of the radial head made no contact at all. At the humeroulnar joint, the articular surfaces were always in contact during some phases of movement. Others have verified these observations. 107 The contact areas on the ulna occurred anteriorly and posteriorly and tended to move together and slightly inward from each side from 0 to 90 degrees of flexion and with increasing load. 31, 74 Using a wax casting technique, in full extension, the contact has been observed to be on the lower medial aspect of the ulna, whereas in other postures, the pressure areas described a strip extending from posterolateral to anteromedial. 37 The radiocapitellar joint also revealed contact during flexion without externally applied load. Investigations in our laboratory show that the contact areas of the elbow occur at four facets: two at the coronoid and two at the olecranon ( Fig. 3-7 ). Only a slight increase in total surface area occurred with elbow flexion and with a sevenfold increase in load. 99 With a 10-N load, about 9% contact of the articular surfaces occurs, and with 1280 N, the area increased to about 73%. 31

FIGURE 3-7 Contact in the sigmoid fossa moves toward the center of the fossa during elbow flexion.
(Redrawn from Walker, P. S.: Human Joints and Their Artificial Replacements. Springfield, IL, Charles C. Thomas, 1977.)
When varus and valgus loads are applied to the forearm, the contact changes medially and laterally. This implies a pivot point about which the radioulnar articulation rotates on the humerus in the anteroposterior (AP) plane in extension with varus and valgus stress. In vivo experiments have demonstrated the varus-valgus pivot point of the elbow to reside in the midpoint of the lateral face of the trochlea ( Fig. 3-8 ).

FIGURE 3-8 The line of action in the muscles produces a compression force at the radial head when situated just lateral to the middle of the lateral face of the trochlea, and a tension force on the radial head is situated just medial to this point. This indicates that the varus-valgus pivot point in the elbow lies at that point on the AP plane.
(From Morrey, B. F., An, K. N., and Stormont, T. J.: Force transmission through the radial head. J. Bone Joint Surg. [Am.] 70:250-256, 1988.)

ELBOW STABILITY
The elbow is one of the most congruous joints of the musculoskeletal system and, as such, is one of the most stable. This feature is the result of an almost equal contribution from the soft tissue constraints and the articular surfaces.
The static soft tissue stabilizers include the collateral ligament complexes and the anterior capsule. Studies from our laboratory regarding the anatomy of the lateral collateral ligament 68, 77 and others 36, 79, 95 have been discussed previously (see Chapter 2 ). The lateral collateral ligament and the anterior bundle of the medial collateral ligament originate from points through which the axis of rotation passes. Furthermore, the medial collateral ligament has two discrete components. 66, 93 The anterior bundle has been shown to be taut in extension; the converse is true for the posterior fibers of the anterior bundle. Because elbow joint motion occurs about a nearly perfect hinge axis through the center of the capitellum and trochlea, the posterior bundle of the medial collateral ligament complex will be taut at different positions of elbow flexion ( Fig. 3-9 ). The lateral collateral ligament and the anterior bundle lying on the axis of rotation will assume a rather uniform tension, regardless of elbow position. Furthermore, the lateral ulnar collateral ligament has inserts on the ulna and, as such, helps to stabilize the lateral ulnohumeral joint ( Fig. 3-10 ). 23, 66, 77, 81 In experiments performed in our laboratory, O’Driscoll and associates have demonstrated that the lateral ulnar collateral ligament is essential to control the pivot shift maneuver (see Chapter 4 ). Further evidence of the contribution of the lateral ligament complex to elbow stability is offered by S∅︀jbjerg and associates. 94 These investigators also attributed a major role in varus and valgus stability to the annular ligament. Although our work suggests that the major component in the varus and rotatory stability is the structure termed the lateral ulnar collateral ligament, the parallel findings of these investigators suggest that the lateral complex is, in fact, a major valgus stabilizer of the elbow joint and functions with or without the radial head. 80

FIGURE 3-9 The anterior medial collateral ligament remains more taut during elbow flexion than does the posterior segment of the ligament. The radial collateral ligament originates at the axis of rotation for elbow flexion; hence, the ligament has little length variation during flexion and extension.
(With permission, Mayo Foundation.)

FIGURE 3-10 The orientation and attachment of the lateral collateral ligament stabilizes the ulna to resist varus and rotatory stresses just as the medial ligament resists valgus stress.

ARTICULAR AND LIGAMENTOUS INTERACTION
The influence of the ligamentous and articular components on joint stability are usually studied with the use of the materials testing machine by imparting a given and controlled displacement to the elbow. 47, 65, 87 The relative contribution of each stabilizing structure can be demonstrated by sequentially eliminating each element and observing the load recorded by the load cell for the constant displacement imparted, usually 2 to 5 degrees 95 ( Fig. 3-11 ).

FIGURE 3-11 Force displacement curves demonstrate relative contribution of elements to elbow stability in extension ( A ) and flexion ( B ).
(From Morrey, B. F., and An, K. N.: Articular and ligamentous contributions to the stability of the elbow joint. Am. J. Sports Med. 11:315, 1983.)
A simplified summary of the observations from such an experiment is shown in Table 3-1 . In extension, the anterior capsule provides about 70% of the soft tissue restraint to distraction, whereas the medial collateral ligament assumes this function at 90 degrees of flexion. Varus stress is checked in extension equally by the joint articulation (55%) and the soft tissue, lateral collateral ligament, and capsule. In flexion, the articulation provides 75% of the varus stability. Valgus stress in extension is equally divided between the medial collateral ligament, the capsule, and the joint surface. With flexion, the capsular contribution is assumed by the medial collateral ligament, which is the primary stabilizer (54%) to valgus stress at this position. Furthermore, for all practical purposes, the anterior portion of the medial collateral ligament provides virtually all of the structure’s functional contribution.

TABLE 3-1 Percent Contribution of Restraining Varus-Valgus Displacement
Limitations of this experimental model have resulted in an overestimation of the role of the radial head inresisting valgus load. 47, 65, 90 This has prompted the development of an experimental technique that allows simultaneous and accurate measurement of three-dimensional angular and translational changes under given loading conditions ( Fig. 3-12 ). Using the electromagnetic tracking device, an accurate technique for measuring the function of the articular and capsuloligamentous structures was developed. 70 More accurate and relevant data were generated. 70 Valgus stability is resisted primarily by the medial collateral ligament. With an intact medial collateral ligament, the radial head does not offer any significant additional valgus constraint. With a released or compromised medial collateral ligament, the radial head does resist valgus stress. This important experiment documents that the radial head is a secondary stabilizer for resisting valgus stress, whereas the medial collateral ligament is the primary stabilizer against valgus force ( Fig. 3-13 ). In a laboratory investigation, the hyperextension trauma produces lesions of the anterior capsule, the avulsion of proximal insertions of both medial and lateral collateral ligaments. 103 The degree of extension increased by 17 degrees and induced significant joint laxity in forced valgus internal-external rotation, but not varus. 103

FIGURE 3-12 The arrangement of the electromagnetic tracking device allows varus-valgus stresses applied to the elbow during simulated motion with the flexor and extensor muscles. Real-time simultaneous three-dimensional motion of the forearm may be monitored with reference to the humerus.

FIGURE 3-13 The stabilizing role of the radial head to valgus stress with the collateral intact resection of the radial head has little effect on valgus stability ( A ). However, if the medial collateral ligament (MCL) has been sectioned, the absence of a radial head markedly increases valgus displacement ( B ). The fact that the radial head is important only when the medial collateral ligament is released defines the radial head as the secondary stabilizer against valgus stress.
It has been recently observed that the valgus and varus laxity of the elbow is dependent on forearm rotation. 86 Increased valgus/varus laxity with forearm pronation, particularly in medial collateral ligament deficient elbows, implies a possible additional factor in throwing kinematics that might put professional baseball pitchers at risk of medial collateral ligament injury due to chronic valgus overload. The forearm rotation should be considered during the clinical examination of elbow instability. The stabilizing effects of monoblock and bipolar designs of radial head replacements in cadaver elbows with a deficient medial collateral ligament were studied. 85 The constraint mechanism inherent in the implant design significantly affected the mean valgus laxity. The implants all performed similarly except in neutral forearm rotation, in which the elbow laxity associated with the Judet implant was significantly greater than that associated with the other two implants.
Comminuted radial head fractures associated with an injury of the medial collateral ligament can be treated with a radial head implant. However, lengthening and shortening of the radial neck by 2.5 mm significantly alters the kinematics and contact pressure through the radiocapitellar joint in the medial collateral ligament-deficient elbow 104 ( Fig. 3-14 ). Radial neck lengthening caused a significant decrease in varus-valgus laxity and ulnar rotation, with the ulna tracking in varus and external rotation. Shortening caused a significant increase in varus-valgus laxity and ulnar rotation, with the ulna tracking in valgus and internal rotation. Therefore, a radial head replacement should be performed with the same level of concern for accuracy and reproducibility of component position and orientation as is appropriate with any other prosthesis.

FIGURE 3-14 Average varus (-) or valgus (+) position of the ulna under different radial neck shortening and lengthening conditions, with the application of valgus (top line) or varus (bottom line) gravitational stress.
(From Van Glabbeek, F., Van Riet, R. P., Baumfeld, J. A., Neale, P. G., O’Driscoll, S. W., Morrey, B. F., and An, K. N.: Detrimental effects of overstuffing or understuffing with a radial head replacement in the medial collateral-ligament deficient elbow. J. Bone Joint Surg. [Am.] 86:2629, 2004.)
Total elbow arthroplasty has been a valuable procedure for treating patients with rheumatoid arthritis, post-traumatic arthritis, osteoarthritis, and failed reconstructive procedures of the elbow. The development of elbow prostheses diverged into two general types: linked and unlinked. The main concern with such development of unlinked elbow replacements is instability, which is attributable to numerous factors including prosthesis design, ligament integrity, and position of the prosthesis. A series of laboratory studies have been performed to examine the intrinsic constraint of various total elbow arthroplasty designs, as well as the joint laxity after implantation in cadaveric specimens 6 ( Fig. 3-15 ).

FIGURE 3-15 Joint laxity for human elbow and with total elbow replacement including the Souter-Strathclyde, Sorbie-Questor, Pritchard ERS, Ewald Capitellocondylar, GSB III, Norway Elbow, and Coonrad Morrey implants.
(From An, K. N.: Kinematics and constraint of total elbow arthroplasty. J. Shoulder Elbow Surg. 14:168S, 2005.)
The contribution of the articular geometry to elbow stability was further evaluated by serial removal of portions of the proximal ulna, as shown in Figure 3-16 . 13 Valgus stress, both in extension and at 90 degrees of flexion, was primarily (75% to 85%) resisted by the proximal half of the sigmoid notch, whereas varus stress was resisted primarily by the distal half, or the coronoid portion of the articulation, both in extension (67%) and in flexion (60%).

FIGURE 3-16 Removal of successive portions of the proximal ulna was studied for its effect on various modes of joint stability. A linear decrease of combined stability is observed, with removal of the olecranon. Note a similar effect for both the extended and the 90-degree flexed positions.
As demonstrated in subsequent chapters, the central role of the coronoid to provide elbow stability is emerging. As serial portions of the coronoid are removed, the elbow becomes progressively more unstable. If the radial head has been resected, as little as 25% resection causes elbow subluxation at about 70 degrees of flexion. Our preliminary studies indicate at least 50% of the coronoid is necessary for elbow stability if the radial head is removed ( Fig. 3-17 ).

FIGURE 3-17 Ulnohumeral instability increases as increasing amounts of coronoid are removed. Resection of 50% of the coronoid can still be stable, but not if the radial head is excised.

FORCE ACROSS ELBOW JOINT
Study of the force across the elbow joint is not an easy task. The analysis can be performed at various degrees of sophistication. It can be either two-dimensional or three-dimensional, static or dynamic, with or without the hand activities. The clinical implications of these forces are obvious, but the magnitudes are not common knowledge. Consequently, in this section, the factors that affect the force passing through the elbow joint will first be analyzed in detail based on two-dimensional considerations. Then, more realistic data based on three-dimensional analysis will be presented.

TWO-DIMENSIONAL ELBOW FORCE ANALYSIS
In sagittal plane motion, the elbow joint is assumed to be a hinge joint. Forces and moments created at the joint, due to the loads applied at the hand, are balanced by the muscles, tendons, ligaments, and contact forces on the articular surfaces. The amount of tension in the muscles and the magnitude and direction of the joint forces are determined by the external loading conditions as well as the responses of muscles-that is, force distribution among these muscles.
To calculate these forces, a free-body analysis of the forearm and hand isolated at the elbow joint is required. From this analysis, a set of equilibrium equations is obtained:

[1]
in which | F i | = magnitude of the tension in i th muscle;
f xi , f yi = components in x and y direction for the unit vector along the line of action of muscle;
R x , R y = x and y components of the joint contact force;
P, P x , P y = magnitude of the applied forces on the forearm and its associated components; and
r i , r p = moment arms of the muscle force and the applied force to the elbow joint center, respectively
The lines of action of muscles crossing the joint have been reported. 2, 8, 84 In the sagittal plane, based on the magnitude of moment arms, the major elbow muscles consist of biceps, brachialis, brachioradialis, extensor carpi radialis longus, triceps, and anconeus ( Table 3-2 ). The other forearm muscles for the hand and wrist provide various but limited contributions to elbow flexion-extension. Unfortunately, the contributions of these forearm muscles are not consistently reported in the literature.

TABLE 3-2 Physiologic Cross-Sectional Area (PCSA), Unit Force Vector (Fx, Fy), and Moment Arm (r) of Elbow Muscles in Sagittal Plane
Assuming that friction and ligament forces are negligible, the resultant joint constraint force vector should be perpendicular to the arc of the articular surface and pass through the center of curvature of this arc. Thus, the problem of elbow force analysis may be reduced to one of solving the unknown variables R x , R y , and | F i | in equation [1]. However, in reality, even for a simple task, multiple muscles are involved, making the force calculation an indeterminate problem. Methods for resolving these indeterminate problems are thus required.

Single-Muscle Analysis
The simplest case is to consider only one single muscle involved in resisting external force. This type of consideration has been used widely in the literature for two-dimensional force analysis of the musculoskeletal system. The magnitude of the muscle force, f, and the magnitude and orientation of the joint reaction force, R, can be obtained by solving equation [1] with i = 1.

[2]
where ψ, θ and φ are the angles between the forearm axis and the applied force, P, muscle pull, M, and resultant joint force, R, respectively.
Thus, an intimate relationship between the joint force and muscle forces in balancing the externally applied force on the forearm ( Table 3-3 ) exists. The magnitude of muscle force required for balancing the external force reflects the changes of the muscle’s moment arm, or mechanical advantage, with changes of the joint configuration.

TABLE 3-3 Muscle and Joint Forces with Single Muscle *

Effect of Muscle Moment Arm
The effect of a changing muscle moment arm on the resultant joint force is demonstrated graphically in Figure 3-18 . If the loading configuration does not change, both the muscle force and the joint reaction force decrease as the muscle moment arm increases. The orientation of the resultant force also changes from the middle portion of the trochlear notch toward the border of the articular cartilage.

FIGURE 3-18 Effect on the muscle and joint forces by changing the moment arm of the muscle force. For a given externally applied force, the longer moment arm decreases the muscle and joint forces. Also, the resultant joint force and orientation (R 1 , R 2 , R 3 ) are affected by the magnitude of the muscle moment arm.
Clinically, the concept of increasing the moment arm of the biceps muscle by moving the insertion distally has been adopted for increasing weak flexion force of the elbow in patients with brachial plexus injury. 72

Effect of Orientation on Muscle Line of Action
Under the same loading condition, the effect of changing the orientation of the muscle line of action under a constant moment arm is demonstrated ( Fig. 3-19 ). The applied force is again assumed to be perpendicular to the forearm. Both magnitudes of muscle and joint reaction forces change slightly with the change of the muscle’s line of action. However, the orientation of the resultant joint force is sensitive to changes in the muscle force line. The orientation of the resultant joint force, therefore, moves from the central portion of the trochlea toward the rim as the direction of muscle pull relative to the forearm changes from vertical to parallel. This is especially true for the resultant joint force in the trochlear notch brought about by the contraction of the upper arm muscles, whose direction relative to the forearm axis changes with the elbow joint flexion angle. On the other hand, the directions of forearm muscles with respect to the resultant joint forces are thus reasonably constant. When considering the direction of resultant joint forces applied on the trochlea, the effects of upper arm and forearm muscles are just reversed. These changes have been confirmed and directly measured with a force transducer at the proximal radius and different orientation of the line of action of the flexors and extensors. 67

FIGURE 3-19 Effect of changing the orientation of the muscle line of action on the muscle and joint force under a given load. The magnitudes of both muscle and joint forces are not changed, but their orientations are.

Effect of the Moment Arm of External Force
With the orientations and moment arms of the muscles kept constant, the magnitude of muscle force and joint force created to resist the externally applied force decrease proportionally, with the decrease of the moment arm of the external force. This is true, simply because the resultant segmental moment created at the elbow joint due to externally applied load decreases when the moment arm decreases. It should be noticed that the direction of resultant joint force also changes slightly. From the aforementioned results, it is also easy to realize that the magnitude of the muscle and joint force increases proportionally with increases in the magnitude of external force. Therefore, in general, these results are usually expressed in terms of ratio to the external load.

Effect of the Direction of the Externally Applied Force
When the force applied at the wrist changes direction from vertical to horizontal, the effective moment arm of this applied force changes. The resultant segmental moment about the elbow joint center due to this force changes as well ( Fig. 3-20 ). Furthermore, when the resultant segmental moments change from flexion to extension, the required muscles also change from flexors to extensors.

FIGURE 3-20 Effect of changes in the orientation of the applied force (χ), where 90 degrees is perpendicular to the long axis of the forearm.

Effect of Change in Axis of Rotation
The sensitivity of the muscle moment arm to the axis of rotation is a critically important consideration in the clinical setting. Altering the axis by 1 cm anterior, posterior, proximal, and distally has a surprisingly small effect on the muscle moments at the elbow. Such axis changes result in less than 10% change in muscle moment arm values ( Fig. 3-21 ).

FIGURE 3-21 A 1-cm alteration in the axis of flexion shows little effect on muscle moment arms.
In summary, the parametric analysis demonstrates that the magnitude and orientation of the resultant joint forces in the trochlear notch depend very much on whether the upper arm or forearm muscles are used, as well as the location and orientation of the external load applied on the forearm and the joint flexion angle that alters the moment arm and orientation of the muscle line of action. However, alterations of the flexion axis have little impact on muscle moment arm.

Multiple Muscle Analysis
In reality, when external loads are applied on the forearm, multiple muscles are involved, and this makes the analyticdetermination of muscle and joint forces difficult. Because the magnitude and orientation of the resultant joint force are two unknown variables, if more than one muscle force is involved the number of unknown variables exceeds the number of available equations (three). This makes the problem indeterminate, and a nonunique solution will result.
Several methods have been employed to resolve the indeterminate problem. Electromyographic (EMG) data and the physiologic cross-sectional area may be used to provide an additional equation. 35, 49 The most commonly adopted techniques are analytic reduction and optimization methods.
In the reduction method, the redundant unknown variables are systematically eliminated, making the remaining system uniquely solvable. In a two-dimensional analysis, this method is more or less the same as that which considers only one single muscle, as described in the previous section. This method can usually provide the ranges of magnitude and orientation of the resultant joint forces for a given task. However, the technique may give physiologically unreasonable solutions, such as using one single forearm muscle to resist the forearm load. Additional judgment and screening are thus required.
With the use of the optimization method, a unique solution to an indeterminate problem is obtained by minimizing a preselected objective function or cost function. 11 Although the solution to the problem is still nonunique, each solution generally is associated with some physiologic phenomenon or condition on which the objective function is constructed and selected. This technique has been described in more detail elsewhere. 9 Recently, the results based on various object functions have been compared with EMG data regarding the muscles. The dependence of muscle coordination is related more to the degree of freedom considered, and less to the cost function selected. 21
The most commonly used objective functions for resolving the indeterminate force analysis problem include linear and nonlinear weighted combinations of the unknown variables. An analytic model for the determination of muscle force across the elbow joint during isometric loading has been developed. 10 In addition to the equilibrium equations obtained from free-body analysis, constraints for muscle tensions based on the physiologic considerations of muscle length-tension and velocity-tension relationships were included:

[3]
in which F is the magnitude of muscle tension, is the normalized muscle force as adjusted by the muscle length, PCSA represents the muscle physiologic cross-sectional area, and σ is the upper bound of muscle activation level. The maximum stress could be generated by the muscle. The word activation is used to describe both the number of active units (recruitment) and their degree of activity (firing frequency). The muscle force distribution was then determined by using the optimization method of

[4]
in which σ is taken as the upper bound value of overall activation of all muscles. In this analysis, the effects of muscle architecture on the muscle force were examined.

Major Elbow Muscles
We are now in a position to consider several muscles in the solution; these include biceps, triceps, brachialis, and brachioradialis.
For the loading case of force applied nonperpendicularly at the wrist, the solutions of two types of optimization procedures are shown in Table 3-4 . The magnitude (R) and direction (φ) of the resultant joint forces correspond to various loads. The resultant joint force shows more variation along the articular surface with changes of joint flexion ( Fig. 3-22 ). This is because the line of action of the upper arm muscle undergoes a tremendous change in direction with respect to the ulnar axis during flexion, as discussed earlier.

TABLE 3-4 Muscle and Joint Forces in Resisting Flexion Moment by Three Major Flexors *

FIGURE 3-22 Joint force magnitude and direction from an applied load at the wrist at various elbow flexion angles. Family of solutions by using different muscle combinations and solution techniques.
The maximum elbow flexion strength occurs at 90 degrees 59, 71 (see Chapter 5 ). From the measured lifting strength data, the maximal muscle force per unit of cross-sectional area can be calculated to be in the range of 10 to 14 kg/cm 2 . About one third to one half of the maximum lifting force can be generated with the elbow in the extended or 30-degree flexed position. At these positions, a force almost three times the body weight can be encountered in the elbow joint during strenuous lifting at about 30 degrees of flexion ( Table 3-5 ).

TABLE 3-5 Muscle and Joint Forces Under Maximum Flexion Forces
During strenuous actions, the maximum tension that could possibly be provided by each individual muscle is usually considered to be proportional to the physiologic cross-sectional area. This has been carefully measured for muscles crossing the elbow. 8 The potential moment contribution of each muscle at the elbow joint can thus be estimated by multiplying its moment arm by its physiologic cross-sectional area. The moment contributions for all of the muscles crossing the elbow joint have been calculated ( Fig. 3-23 ). Of note, the potential moment in varus appears to be balanced by the valgus moment under all of the functional configurations. When flexed, the flexion potential moment seems to be balanced by the extension moment. However, the extension moment exceeds the flexion moment when the elbow is extended.

FIGURE 3-23 The potential moment contribution of each muscle at the elbow joint was estimated by multiplying the moment arm (cm) of the muscle by its physiologic cross-sectional area (cm 2 ). These diagrams show the contributions to flexion-extension and varus-valgus rotation about the joint center at six elbow and forearm configurations. A, Extended/supinated. B, Extended/neutral. C, Extended/pronated. D, Semiflexed/neutral. E, Flexed/neutral.
(From An, K. N., Hui, F. C., Morrey, B. F., Linscheid, R. L., and Chao, E. Y.: Muscles across the elbow joint: A biomechanical analysis. J. Biomech. 14:659, 1981.)
In constructing these moment potential diagrams, it is assumed that all muscles simultaneously and maximally contract to their optimal lengths. To apply these data for more general conditions, consideration should be given and adjustment made for length-tension and force-velocity relationships. In addition, when activities involve submaximal contraction, a proper scaling system based on experimental measurements, such as EMG, 3, 28, 33, 35, 61 is required. In more refined models, themuscle physiology, including the length-velocity-tension relationship, should be considered. 10, 38 In an analytic modeling, the effect of distal humeral shortening on the triceps force production and thus the elbow extension strength has been demonstrated 48 ( Fig. 3-24 ).

FIGURE 3-24 Length-tension relationship for the triceps with the elbow at 30 degrees of flexion.

Electromyographic Activities of Elbow Muscles
EMG analysis is used to provide scaling systems for the muscle force calculations during submaximal contraction and to show the phasic distribution of muscular activities for a given task.

Flexors
Surface electrodes along the belly of the biceps were first used 100 to record electrical activity during dynamic flexion and extension, with and without load. This early study showed a decrease in biceps activity in pronation compared with supination, and that the biceps acted in extension to “brake” the forearm.
Subsequent studies have presented inconsistent data, but in almost all investigations, the biceps demonstrates no 16 or decreased activity when flexion occurs in pronation. 35, 58, 98 As expected, little influence is reflected in the brachialis muscle with forearm rotation. 35, 98 The brachioradialis demonstrates electrical activity with flexion, especially with the forearm rotated to the neutral position 17, 29 or in pronation. 35, 54, 98
These data are summarized for the 90-degree flexion position, because this is the position of maximum strength 15, 54 and of greatest electrical activity of the elbow flexors 35 ( Fig. 3-25 ).

FIGURE 3-25 Electrical activity of the major elbow flexors at 90 degrees of flexion in different forearm rotation positions.
(From Funk, D. A., An, K. N., Morrey, B. F., and Daube, J. R.: Electromyographic analysis of muscles across the elbow joint. J. Orthop. Res. 5:529, 1987.)

Extensors
EMG investigations of the elbow extensor muscles were first completed by Travill in 1962. 102 The medial head of the triceps and anconeus muscles were found to be active during extension; the lateral and long head of the triceps acted as auxiliaries. The anconeus also was active during resisted pronation and supination. In fact, the anconeus has been demonstrated to be active during flexion and abduction-adduction resisted motions. 35, 83 Thus, the anconeus may be considered a stabilizer of the elbow joint, being active with almost all motions.
In 1972, Currier studied the same muscles at 60, 90, and 120 degrees of elbow flexion. The greatest electrical activity occurred at the 90-degree and 120-degree positions, consistent with the position of greatest strength. 24 Others 55 found there was no difference between position and muscular electrical activity.
EMG data of the elbow muscles have thus provided the following information: (1) the biceps is generally less active in full pronation of the forearm, probably owing to its secondary role as a supinator; (2) the brachialis is active in most ranges of function and is believed to be the “workhorse” of flexion; (3) there is an increase of electrical activity of the triceps with increased elbow flexion, probably secondary to an increased stretch reflex; (4) the anconeus shows activity in all positions and, hence, is considered a dynamic joint stabilizer; and (5) generally speaking, the different heads of the triceps and biceps are active in the same manner through most motion.

Forearm Muscles
Some of the forearm muscles originating at the medial and lateral aspects of the distal humerus had been considered in stabilizing the elbow joint. Flexor carpi ulnaris and flexor digitorum superficialis muscles, because of their positions and proximities over the medial collateral ligaments, were potentially the muscles best suited to provide medial elbow support. 25 However, in the EMG investigations, no significant activities of these muscles were noted when valgus and varus stresses were applied. 35 In a recent study of baseball pitchers with medial collateral ligament insufficiency, the data did not demonstrate increased electrical activity of these muscles. 42 These findings suggested that the muscles on the medial side of the elbow do not supplement the role of medial collateral ligaments. 42

Distributive Forces on the Articular Surfaces
Joint compressive forces on various facets of the elbow joint have been reported in the literature. 3, 73 During the activities of resisting flexion and extension moments at various elbow joint positions, the components of force along the mediolateral direction, causing varus-valgus stress, are small compared with those acting in the sagittal plane directed anteriorly or posteriorly. The resultant joint forces on the trochlea and capitellum have been described in the sagittal plane for flexion ( Fig. 3-26 ) and extension ( Fig. 3-27 ) isometric loads. With the elbow extended and axially loaded, the distribution of stress across the joint has been calculated to be approximately 40% across the ulnohumeral joint and 60% across the radiohumeral articulation ( Fig. 3-28 ). 41, 107 More recently, based on a cadaveric study, 46, 57 it has been noted that with the elbow in valgus realignment, only 12% of the axial load is transmitted through the proximal end of the ulna, but with the elbow in varus alignment, 93% of the axial force is transmitted to proximal ulna. Because of the poor mechanical advantage with the elbow in extension, the largest isometric flexion forces occur in this position (see Fig. 3-27 ). 3, 49 Isometric extension produces a posterosuperior compressive stress across the distal humerus. These analytic calculations have undergone experimental confirmation. Using a force transducer at the proximal radius, the greatest force was transmitted across the radiohumeral joint in full extension, a position in which the muscles have poor mechanical advantage. 68

FIGURE 3-26 Orientation and magnitude of forces at the humeral articular surface during flexion, per unit of force at the hand.
(From Amis, A. A., Dowson, D., and Wright, V.: Elbow joint force predictions for some strenuous isometric actions. J. Biomech. 13:765, 1980.)

FIGURE 3-27 Orientation and magnitude of forces at the humeral articulating surface during extension, per unit of force at the hand.
(From Amis, A. A., Dowson, D., and Wright, V.: Elbow joint force predictions for some strenuous isometric actions. J. Biomech. 13:765, 1980.)

FIGURE 3-28 Static compression of the extended elbow places more force on the radiohumeral than the ulnohumeral joint.
When the elbow is flexed, inward rotation of the forearm against resistance imposes large torque to the joint. The magnitudes have been calculated as approaching twice body weight tension in the medial collateral ligament and three times body weight at the radiohumeral joint. 4 Experimental data from the force transducer study suggest that the analytic estimate is probably too high. The greatest force on the radial head from the transducer data occurs with the forearm in pronation ( Fig. 3-29 ). Even in this position, however, the maximum possible force transmission at the radiohumeral joint was measured as approximately 0.9 times the body weight. 67

FIGURE 3-29 Consistently greater force transmission occurs with the forearm in pronation than in supination. This indicates that a screw-hole mechanism exists with the proximal radial migration occurring during this maneuver.
(From Morrey, B. F., An, K. N., and Stormont, T. J.: Force transmission through the radial head. J. Bone Joint Surg. [Am.] 70:250, 1988.)
Considerably less knowledge is available regarding the distributed forces at the elbow during use. Nicol and associates 73 have demonstrated significant forces with daily activities that not only occur at the radiohumeral and ulnohumeral joints but also are generated in the collateral ligaments. An example of such a force pattern is shown in Figure 3-30 . The actual distributive forces occurring at this joint with daily activity constitute an important avenue of further investigation.

FIGURE 3-30 Distribution of articular and soft tissue forces across the elbow for a selected activity.
(From Nicol, A. C., Berme, N., and Paul, J. P.: A biomechanical analysis of elbow joint function. In Joint Replacement in the Upper Limb. London, Institute of Mechanical Engineers, 1977, p. 45.)

Contact Stress on the Joint Articular Surface
With the magnitude, direction, and point of application of the resultant joint force available, the stress on the articular cartilage can now be determined. 84 Because the joint is not a simple geometric shape, a method based on the concept of a rigid body spring model was adopted for solution. 11 In the results, it was found that if the line of action of the resultant force is at the middle of the articular surface, the stress is almost equally distributed throughout the entire articular surface ( Fig. 3-31A ). On the other hand, as the resultant force is directed toward the margin of the articulation anteriorly or posteriorly, the weight-bearing surface becomes smaller, the maximum compressive stress becomes elevated, and the stress distribution over the joint surface becomes more uneven (see Fig. 3-31B ). It should be further noted that the position of maximum stress does not necessarily correspond with the point of intersection of the resultant joint force through the articular surface. Based on this model, the role of antagonistic muscles on the magnitudesand directions of the resultant joint forces, and thus the articulating pressure distribution and joint stability, were extensively examined ( Fig. 3-32 ). 7

FIGURE 3-31 The contact pressure depends on the direction and magnitude of the resultant compressive force. A, When the resultant force is oriented toward the center of the trochlear notch, a more uniform distribution of pressure is observed. B, When the line of action of the resultant joint force is directed to the rim of the trochlear notch, the weight-bearing surface becomes smaller, and maximum compressive stresses increases.

Finite Element Analysis of Composite Fixation for Total Elbow Prosthesis
In total elbow arthroplasty implant loosening remains a challenging complication. Achieving rigid fixation using a combination of bone ingrowth and cementing should improve the implant longevity. The semiconstrained Coonrad-Morrey elbow prosthesis employs this philosophy. It has shown generally satisfactory clinical results for a variety of cases including inflammatory arthritis and distal humerus fracture. 44, 89 The humeral component of the implant incorporates an anterior flange that has the theoretical benefit of transferring stress from the elbow to the humeral bone and relieving stress concentrations at the vulnerable distal humerus cement interface. Finite element analysis was used to evaluate the biomechanical effects of bone graft between the anterior flange and the bone cortex.
Models were created that consisted of the humeral component of the Coonrad/Morrey elbow prosthesis, bone cement surrounding the implant stem, simulated distal humerus, and bone graft between the distal humerus and anterior flange of the prosthesis. Material properties were prescribed as linear elastic with Poisson ratio of 0.3 and elastic modulus values of implant (E = 114 GPa), humerus (E = 17 GPa), bone cement (E = 3 GPa), and bone graft (E = 0.65 GPa). Perfect bonding between the bone-cement and cement-implant interfaces was assumed.
Permutations of the stem size (4, 6, and 8 inch), graft size (50% of flange length, 100% of flange length, and 150% of flange length), and distal humerus (normal and simulated defect) were evaluated. Loading to the implant was applied for cases of anterior (45 N), posterior (45 N), axial (45 N), 45 degrees posterior (45 N), and torsion (1 N-m) load.
Finite element analysis shows that stress and strain in the distal humerus and distal cement mantle can be reduced 10% to 30% when using a bone graft compared with no bone graft between the anterior flange and the bone cortex ( Fig. 3-33 ). Furthermore, when the distal humerus had a simulated defect of 2 cm, extension of the bone graft more proximally than the anterior flange reduced the stress and strain up to 17% compared with bone graft just under the flange. Finally, when selecting the stem size, there was up to a 15% reduction in distal cement stress and strain when choosing a 6-inch stem over a 4-inch stem or when choosing an 8-inch stem over a 6-inch stem. These findings confirmed the clinical experience that rigid fixation and stress relief due to the anterior flange of the implant reduce the complication rate for primary and revision total elbow arthroplasty.

FIGURE 3-33 Stress transmission through finite element model of elbow prosthesis before ( A ) and after ( B ) placement of bone graft between anterior flange and distal humerus. The bone graft and humerus are cut away to show the internal stress transmission.

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PART II
Diagnostic Considerations
CHAPTER 4 Physical Examination of the Elbow

William D. Regan, Bernard F. Morrey

INTRODUCTION
This chapter deals with the basics of a general comprehensive physical examination of the elbow. Specific and focused features of the examination are pictured with the various conditions described below.

HISTORY
Without question the value of a precise history cannot be overstated. Pain is the most common complaint. The severity of the pain and whether it is intermittent or constant, the quantity and type of analgesia used, and the association of night pain are all important characteristics. The functional compromise experienced, whether it be recreational activity or activities of daily living, should be discussed. Frequently, the patient who has lived with chronic pain, such as that accompanying rheumatoid arthritis, has learned certain accommodative activities that have assisted in lessening or eliminating pain from a conscious level. When considering intervention, it is extremely helpful to determine if the pain is getting better, getting worse, or remaining constant.
Functionally, the elbow is the most important joint of the upper extremity, because it places the hand in space away from or toward the body. It provides the linkage, allowing the hand to be brought to the torso, head, or mouth. Because of this, the examiner must be aware of the interplay of shoulder and wrist function as they complement the usefulness of the elbow. However, a considerable limitation of elevation and abduction function can exist at the shoulder complex without producing an appreciable compromise in most activities of daily living. This is true because only a relatively small amount of shoulder flexion and rotation is necessary to place the hand about the head or posteriorly about the waist or hip, and scapulothoracic motion can compensate for glenohumeral motion loss. Full pronation and supination can be achieved only when both the proximal and distal radioulnar joints are normal. 6, 25
Conditions involving the lateral joint, that is, the radiocapitellar articulation, generally evoke pain that extends over the lateral aspect of the elbow with radiation proximally to the midhumerus or distally over the forearm. The pain may be superficial, directly over the lateral epicondyle or radial head, for example, or deep, localized poorly in the area of the proximal common extensor muscle mass supplied by the posterior interosseous nerve. For reasons that remain unclear, the posterior lateral ulnohumeral joint appears to be a “watershed” referral point for a spectrum of remote conditions. Less commonly, nonspecific symptoms poorly localized to the medial aspect of the elbow can represent ulnar nerve pathology, medial epicondylitis or arthrosis.
As is well known, symptoms from cervical radiculopathy can usually be distinguished by a specific radicular distribution of pain and associated neurologic abnormality of the upper extremity. Today, a suspicion of cervical etiology is readily resolved with the magnetic resonance imaging (MRI) scan.

PHYSICAL EXAMINATION

INSPECTION
Considerable information can be ascertained from careful visual inspection of the elbow joint. Because much of the joint is subcutaneous, any appreciable alteration in the skeletal anatomy is usually obvious. Gross soft tissue swelling or muscle atrophy is also easily observed.

AXIAL ALIGNMENT
Axial malalignment of the elbow, when compared with the opposite side, suggests prior trauma or a skeletal growth disturbance. To determine the carrying angle, the forearm and hand should be supinated and the elbow extended; the angle formed by the humerus and forearm is then determined ( Fig. 4-1A ). Although there is considerable variation with race, age, sex, and body weight, an average of 10 degrees for men and 13 degrees for women has been calculated as the mean carrying angle from several reports. 3, 4, 13, 14

FIGURE 4-1 A, The carrying angle is a clinical measurement of the angle formed by the forearm and the humerus with the elbow extended. B and C, The normal 10- to 15-degree carrying angle can be altered by injury about the elbow, causing a varus carrying angle, or so-called gunstock deformity.
Angular deformities, such as cubitus varus or valgus, are also easily identifiable (see Fig. 4-1B and C ). The elbow moves from a valgus to varus alignment as with flexion. In a post-traumatic condition, however, abnormalities in the carrying angle cannot be accurately assessed in the presence of a significant flexion contracture (see Chapter 3 ). Rotational deformities following supracondylar or other fractures of the humeral shaft may be difficult to perceive.

LATERAL ASPECT
Fullness about the infracondylar recess just inferior to the lateral condyle of the humerus, the “soft spot,” suggests either an increase in synovial fluid, synovial tissue proliferation, or radial head pathology, such as fracture, subluxation, or dislocation ( Fig. 4-2 ). Subtle evidence of effusion can be determined by observing fullness in this area.

FIGURE 4-2 A normal depression in the contour of the skin in the intracondylar recess (arrowhead) ( A ) becomes obliterated in the presence of synovitis or effusion ( B ).
Thin, taut, adherent skin over the lateral epicondyle may be indicative of excessive cortisone injections in this area for refractory lateral epicondylitis (see Chapter 44 ). A prominence involving the lateral triangle often indicates a posteriorly dislocated radial head ( Fig. 4-3 ; see Fig. 4-22A and B ).

FIGURE 4-3 Developmental posterior dislocation of the radial head ( A ) is associated with obvious prominence ( B ). Typically, this problem is associated with only minimal limitation of function.

FIGURE 4-22 A, The patient has done a push-up with hands in neutral and his arms wider than shoulder (valgus) and is at a terminal extension (axial load) of his unaffected elbow. He has apprehension in his affected left elbow (axial load + valgus). B, A close-up of the posterolateral dislocation.

POSTERIOR ASPECT
A prominent olecranon suggests a posterior subluxation or migration of the forearm on the ulnohumeral articulation. Occasionally, marked distortion is associated with surprisingly satisfactory function ( Fig. 4-4 ). Rupture of the triceps tendon at its insertion should be suspected if this finding is accompanied by loss of active extension. Loss of terminal passive extension of the elbow is a sensitive but nonspecific indicator of intra-articular pathology. Loss of active motion with full passive extension suggests either mechanical (triceps avulsion) or neurologic conditions.

FIGURE 4-4 Gross deformity of the elbow from a malunion of a condylar fracture. The excellent function is typical of condylar but not T-Y type malunions.
The prominent subcutaneous olecranon bursa is readily observed posteriorly when it is inflamed or distended ( Fig. 4-5 ). Rheumatoid nodules frequently are found on the subcutaneous border of the ulna (see Chapter 74 ).

FIGURE 4-5 An inflamed or enlarged olecranon bursa is one of the more dramatic diagnoses made by observation in the region of the elbow.
(From Polley, H. G., and Hunder, G. G.: Rheumatologic Interviewing and Physical Examination of the Joints, 2nd ed. Philadelphia, W.B. Saunders Co., 1978.)

MEDIAL ASPECT
On occasion the ulnar nerve may be observed to displace anteriorly during flexion with recurrent subluxation of the ulnar nerve. 8 Otherwise, few landmarks are observable from the medial aspect of the joint. The prominent medial epicondyle is evident unless the patient is obese.

ASSOCIATED JOINTS AND NEURAL FUNCTION
No examination of the elbow is complete without a review of the cervical spine and all other components of the upper extremity. If the elbow pain has a radicular pattern, it is important to review the patient’s cervical spine alignment and range of motion and perform neurologic testing of the entire upper extremity. The main nerve roots involved with elbow function are C5-7 ( Fig. 4-6 ). There is considerable overlap in the sensory dermatomes of the upper extremity. The general distribution of sensory levels includes C5, the lateral arm; C6, the lateral forearm; C7, the middle finger; and C8 and T1, the medial forearm and arm dermatomes, respectively.

FIGURE 4-6 The biceps, brachioradialis, and triceps reflexes allow evaluation of the C5, C6, and C7 nerve roots, respectively.
Biceps function from innervation of C5-C6 is a flexor of the elbow and forearm supinator. The reflex primarily tests C5 and some C6 competency. The C6 muscle group of most interest is the mobile wad of three, consisting of the extensor carpi radialis longus and brevis and the brachioradialis muscles. These also are known as the radial wrist extensors and should be assessed for strength and reflex integrity. The reflex is primarily a C6 function, with some C5 component. The primary elbow muscle innervated by C7 is the triceps, which should always be assessed for strength and reflex. Wrist flexion and finger extension also are primarily supplied by C7, with some C8 innervation (see Fig. 4-6 ).
Elbow pain may be referred from the shoulder; therefore, a visual inspection of the shoulder for muscle wasting and appearance should be made, followed by an appropriate functional assessment. Specific attention should be directed toward motion and the spectrum of impingement tendinitis or rotator cuff pathology which often is manifested by pain in the brachium.
For normal forearm rotation, there must be a normal anatomic relationship between the proximal and distal radioulnar joint. Inflammatory changes involving either the elbow or the wrist or both will cause a loss of forearm rotation. Disruption of the normal relationship of the distal radioulnar joint will cause dorsal prominence of the distal ulna exaggerated by pronation and is lessened by supination. Because pronation is the common resting position of the hand, dorsal subluxation of the ulna at the wrist is often identifiable by inspection.

PALPATION

OSSEOUS LANDMARKS
Inspection and palpation of the medial and lateral epicondyles and the tip of the olecranon form an equilateral triangle when the elbow is flexed ( Fig. 4-7 ). Fracture, malunion, unreduced dislocation, or growth disturbances involving the distal end of the humerus can be assessed clinically in this fashion.

FIGURE 4-7 With the elbow flexed to 90 degrees, the medial and lateral epicondyles and tip of the olecranon form an equilateral triangle when viewed from posterior. When the elbow is extended, this relationship is changed to a straight line connecting these three bony landmarks ( A ). The relationship is altered with displaced, intra-articular distal humeral fractures ( B ).

LATERAL ASPECT
The lateral supracondylar region, which we call the lateral column, is readily palpable and is a valuable landmark during lateral surgical exposures ( Fig. 4-8 ) (see Chapters 7 and 32 ). The definition of the location of the extensor carpi radialis brevis is carefully sought and is enhanced by radial wrist and elbow extension. Examination of the radial head is easily performed provided a joint effusion is not present. Digital pressure over the peripheral articular surface of the radial head, when combined with pronation and supination of the forearm in varying degrees of elbow flexion, will offer valuable information about this bony structure and the status of the synovium. If painful, this examination should be performed gently. Radial head or capitellar fracture thus may be suspected even when the radiographic results are negative. An effusion of the elbow is most easily identified by palpation over the lateral borderof the radial head or about the posterior recess located just between the radial head and the lateral border of the olecranon ( Fig. 4-9 ). A radio/humeral plica is appreciated by palpating the snapping of the plica with flexion and extension. As with other joints, significant effusions of hemarthrosis will limit extremes of motion, especially extension. If tense, the elbow will assume a position of maximum joint capacity, which is 80 degrees. 19 Palpation of the arcade of Froshe, located approximately 2 cm anterior and 3 cm distal to the lateral epicondyle, locates the posterior interosseous nerve.

FIGURE 4-8 The lateral supracondylar interval is an avascular area that can be readily palpated and serves as an important landmark in many surgical exposures to the elbow.
(From Hoppenfeld, S.: Physical Examination of the Spine and Extremities. New York, Appleton-Century-Crofts, 1976.)

FIGURE 4-9 The radial head may be readily palpated. The contour and integrity of the structure may be further appreciated by pronating and supinating the forearm during this examination.

MEDIAL ASPECT
Because of the tight ligament and capsule present on the medial side of the olecranon, great difficulty is encountered in assessment of the soft tissues in this area. Palpation of the cubital tunnel is easily performed to assessthe status of the ulnar nerve ( Fig. 4-10 ). A subluxing nerve is identified with flexion and extension. Entrapment is assessed by performing a Tinel test proximal to, at, or distal to the cubital tunnel.

FIGURE 4-10 Palpation of the cubital tunnel. The ulnar nerve is identified proximal and distal to the medial epicondyle.
The flexor-pronator muscles consist of four muscles taking origin from the medial epicondyle. Wrist flexion and pronation against resistance often accentuate the pain and is consistent with a diagnosis of medial epicondylitis.
The medial collateral ligament is the elbow’s primary stabilizer to valgus strain. It takes its origin slightly anterior and inferior to the medial epicondyle and fans out to attach along the greater sigmoid fossa of the ulna with both an anterior and a posterior thickening. 24 With the elbow in 30 to 60 degrees of flexion, it should be palpated for tenderness along its course. Valgus stress is painful if the ligament is injured.

POSTERIOR ASPECT
The olecranon bursa overlies the triceps aponeurosis, which inserts on the olecranon. This area should be palpated for thickening and pain. On occasion, a spur or bony prominence may be readily palpable at the tip of the olecranon (see Chapter 84 ).
With elbow flexion, the olecranon fossa may be identified in a thin person by careful palpation. A tense effusion is likewise detectable from this aspect. The posteromedial olecranon and ulnohumeral joint should be carefully palpated. This is a common site for olecranon spur formation and is painful with forced extension. To accentuate this pain, the elbow is snapped into full extension. The subcutaneous border of the olecranon and proximal ulna also are readily appreciated by palpation.

ANTERIOR ASPECT
The cubital fossa is bordered laterally by the brachioradialis and medially by the pronator teres muscles. There are four significant structures passing through the cubital fossa from lateral to medial, including (1) the musculocutaneous nerve, (2) the biceps tendon, (3) the brachial artery, and (4) the median nerve.
The musculocutaneous nerve supplying lateral forearm sensation is located deep to the brachioradialis between it and the biceps tendon and is not readily palpable. The biceps tendon is readily palpable with resisted forearm supination. The tendon should be assessed for tenderness and for continuity distally. A medial expansion, the lacertus fibrosus, is noted, which covers the common flexor muscle group as well as the brachial artery and median nerve and may be the source of compression of the median nerve. The pulse of the brachial artery is easily located, lying deep to the lacertus fibrosus ( Fig. 4-11 ).

FIGURE 4-11 The lacertus fibrosus is easily palpable at its medial margin, and this covers the brachial artery, median nerve, and becomes attenuated with the distal biceps tendon disruption.

MOTION
Perhaps no portion of the physical examination is more important than the assessment of motion. Loss of full extension is the first motion altered by most pathology. As a matter of fact, in a trauma situation, the likelihood of significant joint pathology in the face of normal elbow motion is so small as not to require radiographic analysis! 15
Normally, the arc of flexion-extension, although variable, ranges from about 0 to 140 degrees plus or minus 10 degrees ( Fig. 4-12 ). 1, 7, 26 This range exceeds that which is normally required for activities of daily living. 17 Pronation-supination may vary to a greater extent than the arc of flexion-extension. Acceptable norms ofpronation and supination are 75 and 85 degrees, respectively ( Fig. 4-13 ). In assessing motion, the examiner should record both active and passive values. The humerus is placed in a vertical position when evaluating the arc of forearm rotation. Patients will tend to accommodate for loss of pronation by abducting the shoulder. Any significant difference between active and passive ranges of motion suggests pain or motor function as the cause. In patients with a flexion or extension contracture, the examiner should concentrate on solid or soft end points, pain or crepitus during the arc and at the end points.

FIGURE 4-12 The normal flexion and extension of the elbows is from zero to approximately 145 degrees. The functional arc of flexion and extension about which most daily activities are achieved is 30 to 130 degrees.

FIGURE 4-13 Normal pronation and supination is about 80 and 85 degrees, respectively. The functional arc of forearm rotation consists of approximately 50 degrees of pronation and 50 degrees of supination.
The examiner should then make a careful assessment of any compromised motion at the shoulder or wrist. Often, the disability will arise from a combination of factors, but it should be stressed that a full range of motion at the elbow is not essential for performance of the activities of daily living. The essential arc of elbow flexion-extension required for daily activities ranges from about 30 to 130 degrees. 17 Because the loss of extension up to a certain degree only shortens the lever arm of the upper extremity, flexion contractures of less than 45 degrees may have little practical significance, although patients sometimes are concerned about the cosmetic appearance ( Fig. 4-14 ).

FIGURE 4-14 Illustration of the marked functional limitation associated with an ankylosed elbow at 90 degrees. Notice the shoulder poorly compensates for the overall effect of limited flexion and extension in both the sagittal ( A ) and the transverse ( B ) planes.
To perform 90% of required daily activity, 50 degrees of pronation and supination are required (see Fig. 4-13 ). 17 For most individuals, pronation is the most important function on the dominant side for eating and writing, and loss of pronation is compensated by shoulder abduction. On the other hand, a loss of supination of the nondominant side may significantly hinder personal hygiene needs, accepting objects, and opening of door handles. These tasks are poorly compensated by shoulder or wrist function.

STRENGTH
Only gross estimates of strength are attainable in the clinical setting. Flexion and extension strength testing ( Fig. 4-15 ) is conducted against resistance, with the forearm in neutral rotation and the elbow at 90 degrees of flexion. Extension strength is normally 70% that of flexion strength 2 and is best measured with the elbow at 90 degrees of flexion, and with the forearm in neutral rotation. 10, 22, 23, 27 Pronation ( Fig. 4-16 ), supination, and grip strength are also best studied with the elbow at 90 degrees of flexion and the forearm in neutral rotation. Supination strength is normally about 15% greater than pronation strength. 2 The dominant extremity is about 5% to 10% stronger than the nondominant side, and women are 50% as strong as men (see Chapter 5 ). 2

FIGURE 4-15 Flexion strength is best assessed with the elbow flexed to 90 degrees and the forearm in neutral rotation. Flexion resistance is assessed while the examiner attempts to extend the elbow ( A ). To test extension strength, the examiner applies resistance to the patient’s ability to extend the elbow with the joint in approximately 90 degrees of flexion and the forearm in neutral (or pronated) position ( B ).
(From Hoppenfeld, S.: Orthopedic Neurology. Philadelphia, J. B. Lippincott Co., 1977.)

FIGURE 4-16 Pronation strength is evaluated with the patient comfortable and the elbow at 90 degrees of flexion. Pronation strength is usually measured by grasping the wrist or, less commonly, the hand with the forearm in neutral position or in supination-rotation ( A ). To test supination strength, the forearm is in neutral position or pronation ( B ).

INSTABILITY
In the absence of articular cartilage loss, the mechanical integrity of the radial and ulnar collateral ligaments is difficult to assess because of the intrinsic stability offered by the closely approximated surfaces of the olecranon and trochlea and the buttressing effect of the radial head against the capitellum. However, when articular cartilage has been destroyed, as in rheumatoid arthritis, or removed, as with radial head excision, collateral ligament stability can be determined by the application of varus and valgus stresses. Medially, the fibers become taut in an ordered sequential fashion, proceeding from anterior to posterior as the elbow is flexed. 22 Accordingly, a portion of the complex is always in tension throughout the arc of flexion (see Chapter 3 ). 24
The radial collateral ligament resists varus stress throughout the arc of elbow flexion with varying contributions of the anterior capsule and articular surface in extension (see Chapter 3 ). The lateral collateral ligament complex consists of the radial collateral ligament (RCL) and the lateral ulnar collateral ligament (LUCL). The RCL maintains consistent patterns of tension throughout the arc of flexion. 24 To properly assess collateral ligament integrity, the elbow should be flexed to about 15 degrees. This relaxes the anterior capsule and removes the olecranon from the fossa. Varus stress is best applied with the humerus in full internal rotation. Valgus instability is best measured with the arm in 10 degrees of flexion ( Fig. 4-17 ). In recent years, we have used the fluoroscan routinely to assess all elbows in where a possible instability exists (see Fig. 4-17C ).

FIGURE 4-17 A, Varus instability of the elbow is measured with the humerus in full internal rotation and a varus stress applied to the slightly flexed joint. B, Valgus instability is evaluated with the humerus in full external rotation while a valgus stress is applied to the slightly flexed joint. C, Examination under fluroscopy readily reveals medial ligament insufficiency.

ROTATORY INSTABILITY
The lateral collateral complex also includes a narrow but stout band of ligamentous tissue blending with the distal and posterior fibers of the capsule to insert distally on the crista supinatoris of the ulna. This is the lateral ulnar collateral ligament. 20, 24
Insufficiency of the lateral collateral ligament is responsible for posterolateral instability of the elbow. 20 Posterolateral instability is elicited in two ways (see Chapter 44 ). The more sensitive is by flexing the shoulder and elbow 90 degrees, with the patient supine. The patient’s forearm is fully supinated, and the examiner grasps the wrist or forearm and slowly extends the elbow while applying valgus and supination movements and an axial compressive force ( Fig. 4-18 ). This produces a rotatory subluxation of the ulnohumeral joint; that is, the rotation dislocates the radiohumeral joint posterolaterally by a coupled motion. As the elbow approaches extension, a posterior prominence (the dislocated radiohumeral joint) is noted with an obvious dimple in the skin proximal to the radial head ( Fig. 4-19 ). Additional flexion results in a sudden reduction as radius and ulna visibly snap into place on the humerus ( Fig. 4-20 ). Alternatively, simply asking the patient to rise from a chair may also reproduce the symptomatology ( Fig. 4-21 ). Finally, having the patient do a push-up places the elbow in the at-risk position ( Fig. 4-22 ). These latter two tests are active apprehension signs.

FIGURE 4-18 The pivot shift maneuver consists of extending the elbow with a valgus axial stress while the forearm is supinated and the elbow is being extended. The elbow tends to sublux toward full extension. A palpable snap or pop is felt with flexion and represents reduction.

FIGURE 4-19 Gross appearance and radiograph of a patient with the positive pivot shift maneuver. Note the dimple in the skin.
(From O’Driscoll, S. W.: Posterolateral rotatory instability of the elbow. J. Bone Joint Surg. 73A:440, 1991.)

FIGURE 4-20 With partial flexion or sometimes simple pronation of the forearm, the elbow is reduced and the dimple is obliterated.
(From O’Driscoll, S. W.: Posterolateral rotatory instability of the elbow. J. Bone Joint Surg. 73A:440, 1991.)

FIGURE 4-21 Using the arms to rise from a chair can replicate the instability pattern of posterolateral rotatory instability (PLRI).

References

1 American Academy of Orthopedic Surgeons. Joint Motion: Method of measuring and recording. Chicago: American Academy of Orthopedic Surgeons, 1965.
2 Askew L.J., An K.N., Morrey B.F., Chao E.Y. Functional evaluation of the elbow: normal motion requirements and strength determination. Orthop. Trans . 1981;5:304.
3 Atkinson W.B., Elftman H. The carrying angle of the human arm as a secondary symptom character. Anat. Rec . 1945;91:49.
4 Beals R.K. The normal carrying angle of the elbow. Clin. Orthop . 1976;119:194.
5 Beetham W.P.Jr., Polley H.F., Slocumb C.H., Weaver W.F. Physical Examination of the Joints. Philadelphia: W. B. Saunders Co., 1965.
6 Bert J.M., Linscheid R.L., McElfresh E.C. Rotatory contracture of the forearm. J. Bone Joint Surg . 1980;62A:1163.
7 Boone D.C., Azen S.P. Normal range of motion of joints in male subjects. J. Bone Joint Surg . 1979;61A:756.
8 Childress H.M. Recurrent ulnar nerve dislocation at the elbow. Clin. Orthop . 1975;108:168.
9 Daniels L., Williams M., Worthingham C. Muscle Testing: Techniques of Manual Examination, 2nd ed. Philadelphia: W. B. Saunders Co., 1946.
10 Elkins E.C., Ursula M.L., Khalil G.W. Objective recording of the strength of normal muscles. Arch. Phys. Med. Rehabil . 1951;33:639.
11 Hoppenfeld S. Physical Examination of the Spine and Extremities. New York: Appleton-Century-Crofts, 1976.
12 Johansson O. Capsular and ligament injuries of the elbow joint. Acta Chir. Scand. Suppl . 1962;287:1.
13 Keats T.E., Teeslink R., Diamond A.E., Williams J.H. Normal axial relationships of the major joints. Radiology . 1966;87:904.
14 Lanz T., Wachsmuth W. Praktische Anatomie. Berlin: ARM, Springer-Verlag, 1959.
15 Lennon R.I., Riyat M.S., Hilliam R., Anathkrishnan G., Alderson G. Can a normal range of elbow movement predict a normal elbow x-ray? Emerg Med J . 2007;24:86.
16 McRae R. Clinical Orthopedic Examination. London: Churchill Livingstone, 1976.
17 Morrey B.F., Askew L.J., An K.N., Chao E.Y. A biomechanical study of normal functional elbow motion. J. Bone Joint Surg . 1981;63A:872.
18 Morrey B.F., Chao E.Y. Passive motion of the elbow joint. A biomechanical study. J. Bone Joint Surg . 1979;61A:63.
19 O’Driscoll S.W., Morrey B.F., An K.N. Intra-articular pressuring capacity of the elbow. Arthroscopy . 1990;6:100.
20 O’Driscoll S.W., Morrey B.F., An K.N. Intra-articular pressuring capacity of the elbow. J. Bone Joint Surg . 1991;73A:440.
21 O’Neill O.R., Morrey B.F., Tanaka S., An K.N. Compensatory motion in the upper extremity after elbow arthrodesis. Clin. Orthop . 1992;281:89.
22 Provins K.A., Salter N. Maximum torque exerted about the elbow joint. J. Appl. Physiol . 1955;7:393.
23 Rasch P.J. Effect of position of forearm on strength of elbow flexion. Res. Q . 1955;27:333.
24 Regan W.D., Korinek S.L., Morrey B.F., An K.N. Biomechanical study of ligaments about the elbow joint. Clin. Orthop . 1991;271:170.
25 Schemitsch E.H., Richards R.R., Kellam J.F. Plate fixation of fractures of both bones of the forearm. J. Bone Joint Surg . 1989;71B:345.
26 Wagner C. Determination of the rotary flexibility of the elbow joint. Eur. J. Appl. Physiol . 1977;37:47.
27 Williams M., Stutzman L. Strength variation through the range of motion. Phys. Ther. Rev . 1959;39:145.
28 Youm Y., Dryer R.F., Thambyrajahk K., Flatt A.E., Sprague B.L. Biomechanical analysis of forearm pronation-supination and elbow flexion-extension. J. Biomech . 1979;12:245.
CHAPTER 5 Functional Evaluation of the Elbow

Bernard F. Morrey, Kai-Nan An

INTRODUCTION
Involvement of the upper limb accounts for about 10% of all compensation paid in the United States for disabling work-related injuries. 47, 67 In addition, dysfunction of the upper extremity cost about 5.5 million lost work days in 1977. 66 Elbow function consists of three activities: (1) allows the hand to be positioned in space, (2) provides the power to perform lifting activities, and (3) stabilizes the upper extremity linkage for power and fine work activities. The essential joint functions are motion, strength, and stability. However, ultimately, the final determinant of function and the ability to perform activities of daily living is pain.

ELBOW MOTION

NORMAL MOTION
Normal flexion and forearm rotation at the elbow are adequately measured clinically with the handheld goniometer. Forearm rotation is measured with the elbow at 90 degrees of flexion, often with the subject holding a linear object, such as a pencil, to make the measurement more objective. 79 In spite of obvious limitations, investigators have concluded that a standard handheld goniometric examination by a skilled observer allows measurement of elbow flexion-extension and pronation-supination with a margin of error of less than 5%. 35, 95 In fact, the flexion-extension intraobserver reliability correlation coefficient is 0.99. 78 Different trained observers also provide measurements that are statistically equivalent. 30, 78
Normal passive elbow flexion ranges between 0 and 140 to 150 degrees. 1, 11, 44, 79 Greater variation of normal forearm rotation has been described but averages about 75 degrees pronation and 85 degrees supination. 1, 11, 44, 91

INVESTIGATIVE TECHNIQUES OF MEASURING COMPLEX ACTIVE MOTION
To measure the three-dimensional joint motion in daily activities, any one of several rather sophisticated experimental techniques can be used. 1, 95 For experimental studies, the triaxial electrogoniometer 2, 16, 63 can simultaneously measure three-dimensional motion of more than one joint system with a high degree of reproducibility and reliability 58, 71 ( Fig. 5-1 ). Video telemetry, computer-simulated motion, and electromagnetic sensors have also been developed to study three-dimensional kinematic measurement. 2, 71, 87 Most recently, robotic techniques and miniature accelerometers and gyroscopes have been adopted to study complex upper extremity compensatory motion. 49, 56 For the elbow, the complex inter-relationship of shoulder and wrist function, both motion and motor activity, remains a complex and poorly understood area of investigation. 32

FIGURE 5-1 The elbow electrogoniometer may be used to measure activities of daily living. A, Elbow flexion and forearm rotation to reach the back of the head. B, The subject is sitting at the activities table.
(From Morrey, B. F., Askew, L. J., and Chao, E. Y.: A biomechanical study of normal functional elbow motion. J. Bone Joint Surg. 63A:872, 1981.)

FUNCTIONAL MOTION
For most activities, the full potential of elbow motion is not needed or used. Loss of terminal flexion is more disabling than is the same degree of loss of terminal extension. 14, 70 Using the electrogoniometer just described, a study of 15 activities of daily living established that most functions can be performed using an arc of 100 degrees of flexion between 30 and 130 degrees ( Fig. 5-2 ) and 100 degrees of forearm rotation equally divided between pronation and supination ( Fig. 5-3 ). This has become the accepted standard for functional elbow motion.

FIGURE 5-2 Normal elbow flexion positions for activities of hygiene and those requiring arcs of motion are demonstrated. Most functions can be performed between 30 and 130 degrees of elbow flexion.

FIGURE 5-3 Routine daily activities requiring pronation and supination or arcs of motion are performed between 50 degrees pronation and 50 degrees supination.
The motion requirements of the elbow joint needed for daily activities are really a measurement of the reaching ability of the hand. The extent to which this function is impaired by loss of elbow flexion or extension can be estimated analytically ( Fig. 5-4 ). When motion is limited from 30 to 130 degrees, the potential area reached by the hand is reduced by about 20%. Thus, the range of elbow flexion between 30 and 130 degrees corresponds with about 80% of the normal reach capacity of the forearm and hand in a selected plane of shoulder motion. The functional impact of further loss of the flexion arc is also not equally distributed between flexion and extension. Our clinical experience indicates that flexion is of more value than extension in a ratio of about 2:1. Hence, a 10-degree further loss of flexion (120 degrees) is roughly equivalent to 20 degrees further loss of extension ( Fig. 5-5 ).

FIGURE 5-4 The reaching area of the hand in the sagittal (A) and transverse (B) planes, with simultaneous movement of the elbow and shoulder. If the elbow is held at approximately 90 degrees of flexion, marked reduction of reach potential occurs. Note also that the circumduction motion of the shoulder does not compensate for the hinged type motion of the elbow joint.

FIGURE 5-5 The further loss of motion from the ideal 30 to 130 degree arc is better tolerated as extension loss than as flexion loss.
The optimal position of elbow fusion to accomplish activities of daily living has been accepted as 90 degrees. 86 To further assess this issue, we hypothesized that the optimal position would be associated with a minimal amount of compensatory shoulder motion. 71 It was surprising to observe that for discrete and fixed positions of the elbow, increasing the amount of shoulder motion did not provide greater use or increased function. It was also noted that for greater degrees of fixed elbow flexion, efforts to perform daily functions were accompanied by a tendency of the humerus to assume a less elevated and more lateral circumduction position ( Fig. 5-6 ). This is consistent with the mechanical functions of these two joints; a ball-and-socket joint providing rotatory motion does not provide compensatory motion for hinge-type motion that occurs only in a single plane. This investigation did confirm the accepted tenant that 90 degrees is the optimum position or “least worse” for most activities.

FIGURE 5-6 As the fixed position of elbow fusion increases toward 90 degrees, activities of daily living are accomplished with the humerus less elevated and more laterally circumducted.

STRENGTH
To understand the value and limitations of clinical strength assessment, it will be helpful to briefly review the physiology of muscle contraction and major factors affecting strength. 15

TYPES OF MUSCLE CONTRACTION
There are several types of muscle contraction classified according to changes in length, force, and velocity of contraction ( Fig. 5-7 ). 5, 31, 60

FIGURE 5-7 Types of muscle contractions classified according to change in muscle length. An isometric contraction results in no change of muscle length with a constant load and velocity. The concentric contraction is defined as a shortening of the muscle, whereas the eccentric contraction occurs with lengthening of the muscle. These latter two contractions may be subclassified according to whether a constant load (isotonic) or a constant velocity (isokinetic) condition is met.
If there is no change in muscle length during a contraction, it is called isometric. When the external force exceeds the internal force of a shortened muscle and the muscle lengthens while maintaining tension, the contraction is called an eccentric, or lengthening, contraction. In contrast, if the muscle shortens while maintaining tension, a concentric contraction occurs. For elbow flexion, eccentric force exceeds isometric force by about 20%, and isometric force exceeds concentric force by about 20% ( Fig. 5-8 ). 23, 85 However, it is known that eccentric exercise is associated with muscle fiber damage. This may lead to alterations in muscle receptors that can alter joint position sense. 13

FIGURE 5-8 Comparison of isometric, concentric, and eccentric flexion and extension contraction strength for different positions of elbow flexion. Note that approximately 20% greater strength may be generated with an eccentric than with an isometric contraction; the isometric contraction, on the other hand, is approximately 20% greater than the concentric type of contraction.
(Modified from Singh, M.: Isotonic and isometric forces of forearm flexors and extensors. J. Appl. Physiol. 21:1436, 1966.)

FORCE CONSIDERATIONS
If the muscle produces a constant internal force that exceeds the external force of the resistance, the muscle shortens, and the contraction is further characterized as isotonic . Energy use in this case is larger than that required to produce tension, which will balance the load, and the extra energy is used to shorten the muscle. If the speed of rotation of an exercising limb is predetermined and held constant, changes occur in the amount of tension developed in the muscles causing the motion. This is called an isokinetic contraction. This may be of either the concentric or eccentric type defined earlier.

Speed of Contraction
A rapidly contracting muscle generates less force than one contracting more slowly. In an isometric contraction, the velocity is zero because the resistance exceeds the ability of the muscle to move the joint. In sports, rates of motion exceeding 300 degrees per second are common. One recent study has shown that isometric training at maximum strength is more effective to increase power production than no load training at maximum velocity. 88

FACTORS AFFECTING MAXIMUM MUSCLE TENSION


Muscle Length at Contraction
The relationship of muscle tension to muscle length is recognized by most clinicians and is presented graphically in the form of a length tension curve of an isolated muscle ( Fig. 5-9 ). 27 Recent studies suggest this concept is applicable to muscle systems at different anatomic sites. 89 The exact nature of the relationship varies from muscle to muscle and from joint to joint, depending on the specific function. For example, a study in our laboratory demonstrated the relationship of triceps strength as a function of muscle shortening. A somewhat linear relationship with 1-, 2-, and 3-cm length change associated with 17%, 40%, and 63% strength reduction, respectively 39 ( Fig. 5-10 ). The length of elbow rotators change considerably over the full range of motion. The percent change at the wrist is 8; at the elbow, 55; and at the shoulder, 200. 74

FIGURE 5-9 An idealized length tension curve during isometric contraction demonstrates the maximal force for active muscle contractility. A greater amount of force may be attained if the muscle is stretched to some optimal point. Excessive stretching, although theoretically increasing the muscle force, in fact reduces the strength of contraction owing to loss of the ability of the contractile elements to function optimally.

FIGURE 5-10 Effect of the change in triceps length on extension strength.

TECHNIQUE OF STRENGTH MEASUREMENT
When evaluating strength, either the torque created about the joint or the force generated in the hand and forearm in resisting joint rotation is measured. Either static or dynamic measuring devices may be used.
In the clinic, the most common study is that of static or isometric flexion-extension strength using a simple tensiometer, or spring device ( Fig. 5-11 ). 17, 52 For more accurate documentation or for investigative purposes, more sophisticated devices such as a strain gauge tensiometer 25 and dynamometer 21, 64, 76 also have been used.

FIGURE 5-11 A simple spring tensiometer, which is used in the clinical setting to estimate elbow flexion strength.
Isokinetic strength is a more specific measurement of dynamic elbow flexion-extension function and is used more frequently today, especially for the assessment of athletic or occupational injuries. In an isokinetic muscular movement, the speed of rotation of the limb is held constant despite changes in the amount of tension developed. This isokinetic movement can be measured by means of an accommodating resistance dynamometer. Because of the accommodating load cell, the velocity of an exercising limb cannot be increased. 60, 72 As more force is exerted against the lever arm of the dynamometer, more resistance is encountered by the limb, and rotation occurs only at the predetermined constant speed. These devices accurately measure peak torque, the joint angle position at peak torque, the range of motion, and endurance. 6 This technique is becoming increasingly useful for the measurement of elbow strength and endurance, and for more accurate study of the role of fatigue in arriving at disability estimates. 84 This has proven particularly useful in assessing patients with biceps tendon reattachment.

ELBOW STRENGTH

STATIC MEASUREMENTS


Flexion Extension
Although the general tends are relatively consistent, 9 absolute strength measurements are not exactly comparable owing to variations in study technique and even greater differences between individual subjects, especially correlated to body size and age. 10, 41
On the average, the maximum isometric torque created at the elbow joint is about 7 kg-m for men and 3.5 kg-m for women. 4 Isometric muscle power is greatest during flexion at joint positions between 90 and 110 degrees. 25, 93 At elbow angles of 45 and 135 degrees, only about 75 percent of the maximum elbow flexion strength is generated. 43, 45, 94 Maximum flexion strength is generated in forearm supination; forearm pronation is associated with the weakest flexion strength. 18, 43 Most of the torque occurs from contributions of the biceps, brachialis, and brachioradialis. 28
The mean difference in isometric flexion force among the three forearm positions at various flexion angles is about 5% for women and 10% for men. 25 Strengths at the neutral forearm position were slightly greater than those at the supinated and pronated positions. 25, 43, 76, 80
For elbow extension, the average maximum torque strength is about 4 kg-m for men and 2 kg-m for women ( Fig. 5-12 ). 4 Observations for 14 female and 10 male subjects showed a gradual increase in strength as the elbow was extended and the 90 degree position generates the greatest isometric extension force. 20, 28, 53, 76

FIGURE 5-12 Mayo Clinic Biomechanics Laboratory study of normal elbow strength. Notice that men are approximately twice as strong as women and that a 5% to 10% difference is noted between the dominant and nondominant extremities.
In general, the dominant extremity is about 5% to 10% stronger than the nondominant side, and men are about twice as strong as women in most positions (see Fig. 5-12 ). The isometric force of the flexors is about 40 percent greater than the isometric force of the extensors. 4, 45

Supination and Pronation
The greatest supination strength is generated from the pronated position; the converse relationship is also true. 17, 55 In the majority of shoulder elbow positions, the average torque of supination exceeded that of pronation by about 15 to 20 degrees for males and females. This was particularly marked when the elbow was extended. On the average, isometric pronation and supination strengths for men are 80 kg-cm and 90 kg-cm, respectively, and for women are 35 kg-cm and 55 kg-cm, respectively. The dominant and nondominant strength difference in these two types of function averaged about 10% (see Fig. 5-12 ). In one study, 83 it was found that isometric elbow strengths of rheumatoid arthritis patients decreased in proportion to an increase in the severity of x-ray findings. The flexion and supination strengths after total elbow replacement were about two times greater than before operation.

DYNAMIC FUNCTION
Fatigue is an important consideration in altered function because routine activities require repetitive actions, some of which may exceed one million cycles per year. 22
The relative value of static and dynamic testing modalities is a debated issue. Motzkin and colleagues 65 studied the relationship between isometric and isokinetic fatigue and found no consistent relationship. One reason for this is the marked variation even in test-retest studies of the same function. 33 The one reliable association is that the eccentric contracture provides the greatest torque strength for both isometric and isokinetic testing modes. 33, 65
The relationship between strength and speed of movement is undefined. 4 Many investigations support the hypothesis that maximum strength and the rate of movement are independent of each other. 68, 73 In a recent study, 29 isokinetic peak torque and work were greater at the slower speed, as opposed to power, which was significantly greater at the faster speed.

ADDITIONAL VARIABLES OF STRENGTH ASSESSMENT
In addition to the factors discussed, other confounding variables to strength testing include motivation, the learning effect of repetitive tests, 51, 59, 81 the psychological benefit derived from repetitive testing, 37, 54 and the influence of the time of day, 58 age, and even body size. 10, 41 The motivation factor is a variable that is well recognized but is difficult to control, quantitate, or eliminate. 19, 50, 85 The rate of attaining maximum strength during repetitive exertion has been suggested as a possible objective criterion for judging whether a subject is voluntarily exerting full muscular strength or is not giving an honest effort. 50 The eccentric:concentric strength ratios as well as the difference between these ratios at the high and the low speeds were highly effective in distinguishing maximal from submaximal efforts, 24 and we do currently use this information clinically to assess for “functional” behavior.

STABILITY
By virtue of the inherent stability afforded by the joint articulation, clinical instability of the elbow may be a perplexing problem (see Chapters 28 through 30 ). Ligamentous injury most commonly occurs in association with radial head fracture 42, 82 or elbow dislocation. Recurrent dislocations, however, occur in only 1% to 2% of patients. 54 In fact, recurrent instability at the elbow is most commonly a rotatory instability due to insufficiency of the lateral ulnar collateral ligament 69 and is discussed at length in Chapter 48 . The clinical concept of complex instability is becoming more recognized. The “unhappy triad” refers specifically to fractures of the radial head and coronoid in association with collateral ligament injury. Quantification of instability is difficult; studies are being conducted to understand instability, but no well-defined standard exists to clinically grade this parameter (see Chapter 4 ). 8

FUNCTIONAL EVALUATION OF THE ELBOW

PERFORMANCE INDICES
An objective and reproducible means of evaluating the elbow by considering all of these features of function is obviously desirable. A tradeoff exists between a complex but detailed assessment protocol and one that is simple but not sufficiently thorough. A complete and comprehensive assessment that might be useful in a research facility is not practical clinically. For a clinician, a meaningful rating system should be both complete and readily amenable to an office practice ( Table 5-1 ). A single parameter or index composed of all pertinent variables should accurately reflect the gradation of objective function, as discussed earlier. To be of further value, the rating system should include consideration of the presence of pain and specific daily functions that serve as surrogates to several functional variables as they apply to a discrete activity. Finally, it is also realized that no index or system is capable of discriminating changes in function of the full spectrum of pathology. A tool to describe the state of an athlete with tennis elbow is not adequate to describe the dysfunction of rheumatoid arthritis.
TABLE 5-1 Characteristics and Implications of Patient Assessment Tools Trait Implication Short High compliance Reflects reality Valid to draw conclusions Easy Nonambiguous questions Reliable
• Accurate for all respondents
• Effective in person or by communiqué Universal Addresses broad spectrum of conditions Validated   Variation Believable data Reliable Make decisions Accurate Based on outcome
To date, most proposed rating systems consider both objective function and subjective features (motion, strength, stability, pain, and the ability to perform daily activities). 77 Most systems have been developed to document the effectiveness of surgical intervention ( Table 5-2 ). 26, 40, 75 Broberg and Morrey 12 first described a system designed to be applicable not only to joint replacement but also to other reconstructive procedures. However, as noted earlier, it is obvious that no single rating system is both simple and also sensitive enough to distinguish the status and change of function of the person crippled by rheumatoid arthritis and of the professional tennis player with epicondylitis. Nonetheless, I (B.F.M.) have found that a modification of the simple system reported by Broberg has met my clinical needs over the last several years. The currently employed system is termed the Mayo Elbow Performance Score (MEPS) ( Tables 5-2 and 5-3 ). 62 Any discussion of a system or index to summarize function should be subjected to (1) test and retest reliability, (2) internal consistency, and (3) validity.

TABLE 5-2 Functional Assessment and Rating Schemes for the Elbow
TABLE 5-3 Mayo Elbow Performance Score Function Points Definition (Points) Pain 45
None (45)
Mild (30)
Moderate (15)
Severe (0) Motion 20
Arc >100 degrees (20)
Arc 50–100 degrees (15)
Arc <50 degrees (5) Stability 10
Stable (10)
Moderate instability (5)
Gross instability (0) Function 25
Comb hair (5)
Feed (5)
Perform hygiene (5)
Don shirt (5)
Don shoe (5) Total 100  
Classification: excellent, >90; good, 75–89; fair, 60–74; poor, <60.
Furthermore, it is highly desirable to be able to determine the index from patient input above, either in person or by questionnaire. The characteristics of an effective functional evaluation scheme are shown in Table 5-1 . In most systems, 26, 75 pain accounts for the majority of the overall score. Because pain improvement is the most common outcome of intervention, one can bias the appearance of the success of a procedure by overweighing pain in the index calculation. Furthermore, I believe that it is important for the specific functional index used in a clinical practice to represent all functions of the elbow joint as accurately as possible. Thus, those indexes that do not consider strength and stability, except as how they relate to activities of daily living, may not be as comprehensive as those that consider these specific joint functions. 23 The functions of motion, strength, and stability are also tested and, hence, duplicated by the ability to perform activities of daily living. Thus, this latter category is really a surrogate for the other three. The issue of a reliable, comprehensive, and yet simple method of determining functional assessment remains unanswered for the elbow and, at the present time, is the subject of discussion and investigation by the American Shoulder and Elbow Surgeons. Turchin and colleagues 90 recently conducted an extensive assessment of the published elbow rating scores. Although there is a lack of agreement in the aggregate scores, there is good correlation with the individual raw aggregate scores. The most important message is that which reinforces the observation made earlier; there is no one system that accurately reflects therapeutic value for all conditions: athletic, arthritic, traumatic, and the like. In fact, a self administered questionnaire to assess ulnar nerve function has recently been demonstrated to be reproducible and valid. 61

OUTCOME MEASURES
In recent years, an increased emphasis has been placed on the subjective status or the “outcome” of intervention.
The flurry of activity over the last decade has been productive in first producing useful general tools of assessment such as the Short Form-36 43, 46, 92 and the Western Ontario and McMaster University Osteoarthritis Index (WOMAC). The WOMAC is designed principally to asses hip and knee function. 33 More specific to the elbow and upper extremity, the American Shoulder and Elbow Surgeons described a patient- and physician-administered assessment tool, 48 and a global strategy of documenting upper extremity function including the shoulder, elbow and hand (DASH) has been developed 38 by the American Academy of Orthopedic Surgeons in conjunction with the Canadian Institute for Work and Health. 38 The DASH continues to be assessed and refined to further enhance its relevance. 7
Ultimately, the goal is to measure disease and intervention impact on function 36 and quality of life. 3 The Patient-Related Elbow Evaluation is a short form using the Visual Analogue Scale to describe pain and daily function. 57 The goal is to include patient-specific symptoms as well as components of the functional status including physical, social, and psychological aspects to determine the impact of treatment. The value of specific intervention on quality of life has also been undertaken recently. 3 As implied earlier, accurately demonstrating this relationship is surprisingly complex, but by carefully using existing metrics, investigators have objectively documented the positive impact of elbow joint replacement. 3 What remains is to also demonstrate the cost effectiveness of interventions and ultimately be in a position to compare selection factors, techniques, implants, and the like by objective and subjective outcome standards.

References

1 American Academy of Orthopaedic Surgeons. Joint Motion: Method of Measuring and Recording. Chicago: American Academy of Orthopaedic Surgeons, 1965.
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CHAPTER 6 Diagnostic Imaging of the Elbow

Thomas H. Berquist

INTRODUCTION
Imaging technology has expanded dramatically over the past decade ( Box 6-1 ). However, evaluation of the elbow still relies heavily on routine radiographs or computed radiography (CR) images. Optimal hard copy radiographs, or CR images, are essential to properly select additional studies and are required for accurate interpretation of other modalities such as magnetic resonance (MR) imaging. 7

BOX 6-1 Imaging Techniques for Evaluation of the Elbow

Radiography/CR imaging
AP, lateral, oblique, radial head, and axial views
Stress views
Computed tomography (CT)
Arthrography
Conventional single- or double-contrast techniquee
CT with coronal and sagittal reformatting
MRI with axial, coronal, and sagittal images
MRI
Ultrasonography
Radionuclide scans/PET
Angiography
AP, anteroposterior; CR, computed radiography; CT, computed tomography; MRI, magnetic resonance imaging; PET, positron emission tomography;
Conventional tomography is rarely performed today. However, computed tomography (CT) has increased in utility with new multidetector systems that provide rapid evaluation of numerous bone and soft tissue disorders. 3 Arthrography also can be an important tool in the diagnosis of intra-articular disorders of the elbow. Today, conventional, CT, and MR arthrography play important roles for evaluating the articular cartilage, intra-articular anatomy, and supporting structures of the elbow. 7
Magnetic resonance imaging (MRI) frequently is used to evaluate subtle osseous and soft tissue abnormalities. Soft tissue contrast is superior to that achieved with CT. MRI scans can be obtained in any plane, which is an additional advantage. Intravenous or intra-articular injection of gadolinium provides additional information in selected cases. 23
Within the scope of this chapter, the indications for diagnostic imaging options as well as their utility in given clinical situations are discussed. Sufficient background information to aid in determining the best modality for a given situation also is presented.

RADIOGRAPHY/COMPUTED RADIOGRAPHY IMAGING
An understanding of the process by which routine radiographs or CR images are obtained is essential. Factors such as the type of equipment, patient positioning, and radiation dose must be kept in mind when determining the necessary views in a given clinical setting. In obtaining views of the elbow, we routinely use a 48-inch target film distance with 50 to 60 kVp, 600 ma, and an exposure time of 0.0125 seconds. Reusable CR or regular cassettes measuring 10 × 12 inches are routinely employed. 1, 4, 5
A minimum of two projections is necessary for evaluation of the elbow. Anteroposterior (AP) and lateral views of the elbow are taken at 90-degree angles and fulfill these criteria. In trauma patients, we routinely obtain oblique views as well. 1, 5
CR uses phosphor plate technology, which is designed to be used in a filmless environment. This technology is replacing conventional screen-film radiography. Regardless of the method of distribution (film or electronic), the techniques for patient positioning and other factors discussed are similar.

ANTEROPOSTERIOR VIEW
The AP view (beam enters the patient anteriorly and the film is posterior) is obtained by placing the patient adjacent to the radiographic table in a sitting position (the supine position may be used if the patient is injured). The patient should be positioned with the extended elbow at the same level as the cassette so that the extremity is in contact with the full length of the cassette. 1, 4 The hand is supinated, and the beam is centered perpendicular to the elbow ( Fig. 6-1A ). The AP view demonstrates the medial and lateral epicondyles and the radiocapitellar articular surface ( Fig. 6-1B ). Assessment of the trochlear articular surface and at least a portion of the olecranon fossa is also possible. The normal carrying angle (5 to 20 degrees, average 15 degrees) can be measured on the AP view. 1, 5

FIGURE 6-1 A, Patient positioned for the anteroposterior (AP) view of the elbow. The arm is level with the cassette, with the hand positioned palm up. The central beam (pointer) is perpendicular to the elbow. B, Radiograph of the elbow in the AP projection with anatomic labels.

LATERAL VIEW
The lateral view is obtained by flexing the elbow 90 degrees and placing it directly on the cassette. The hand is positioned with the thumb up so that the forearm is in the neutral position; the beam is perpendicular to the humerus ( Fig. 6-2A ). This view provides good detail of the distal humerus, elbow joint, and proximal forearm. The coronoid of the ulna, which cannot be readily seen on the AP view, and the olecranon are well visualized on the lateral view (see Fig. 6-2B ). Because the articular surface makes a valgus angle of about 7 degrees to the long axis of the humerus (see Chapter 2 ), a lateral view of the arm does not provide a lateral view of the joint. If the x-ray beam is parallel to the articular surface, three concentric arcs can be identified ( Fig. 6-3A-D ). 5 The smaller arc is the trochlear sulcus, the intermediate arc represents the capitellum, and the largest arc is the medial aspect of the trochlea. If the arcs are interrupted, a true lateral view has not been obtained. Unfortunately, in patients with acute injury, true AP and lateral views are often difficult to obtain. Patients are frequently unable to extend or flex the elbow fully. In these situations, the tube must be angled and the cassette positioned to simulate these views as closely as possible. 1, 4, 5

FIGURE 6-2 A, Patient positioned for the lateral view with the elbow flexed 90 degrees and the beam (pointer) perpendicular to the joint. The shoulder is at the same level as the cassette. This position is required to obtain a true lateral view. B, The projected image.

FIGURE 6-3 A, Dried bone specimen demonstrating the points used for the three concentric arcs. A, capitellum; B, trochlear sulcus; C, medial aspect of trochlea. A true lateral view of the joint requires the beam to be directed distally about 7 degrees. B, On the true lateral view, the three arcs are perfectly aligned. C and D, With slight lateral ( C ) and medial ( D ) rotation of the elbow, the arcs are no longer aligned, indicating that the view is not a true lateral.

OBLIQUE VIEWS
Oblique views are obtained by initially positioning the arm as if one were taking the AP view. For the medial oblique projection ( Fig. 6-4A and B ), the arm is positioned with the forearm and arm internally rotated approximately 45 degrees (see Fig. 6-4A ). This view allows improved visualization of the trochlea, olecranon, and coronoid (see Fig. 6-4B ). The radial head is obscured by the proximal ulna. The lateral oblique view is taken with the forearm, hand, and arm rotated externally ( Fig. 6-5A ). This projection provides excellent visualization of the radiocapitellar joint, medial epicondyle, radioulnar joint, and coronoid tubercle (see Fig. 6-5B ). 1, 4, 5

FIGURE 6-4 Medial oblique view. A, The patient’s arm is internally rotated and the hand pronated. The central beam pointer is perpendicular to the elbow. B, Radiograph of the medial oblique view. The radial head is obscured by the ulna. Note the constant relationship of the radial head and the capitellum.

FIGURE 6-5 Lateral oblique view. A, The patient is positioned with the arm externally rotated, the forearm supinated, and the central beam (pointer) perpendicular to the elbow. B, Radiograph of the lateral oblique view. Note the visualization of the radial head and capitellum, medial epicondyle, and radioulnar joint.

RADIAL HEAD VIEW
Radial head fractures are a common clinical problem and are often difficult to visualize on radiographs or CR images. The radial head view may define the fracture more clearly. 16, 17, 28 This view ( Fig. 6-6A and B ) is easily accomplished by positioning the patient as one would for the routine lateral view. The tube is angled 45 degrees toward the shoulder joint (see Fig. 6-6A ). The radial head view projects the radial head away from the ulna, allowing subtle changes to be more easily identified (see Fig. 6-6B ), and it also may allow better visualization of the fat pads. 1, 16, 17

FIGURE 6-6 Radial head view. A, The patient is positioned as if a routine lateral view (see Fig. 6-2A ) were to be obtained. The tube is angled 45 degrees toward the humeral head rather than perpendicular to the joint. B, Radial head view projects the radial head (R) clear of the olecranon and clearly demonstrates the capitellum (C) and radiocapitellar joint.

AXIAL VIEWS
Occasionally, suspected pathology of the olecranon or epicondyles prompts further evaluation with axial views. Figure 6-7A and B demonstrate the axial projection used to evaluate the epicondyles, olecranon fossa, and ulnar sulcus. The patient’s elbow is flexed approximately 110 degrees, with the forearm on the cassette and the beam directed perpendicular to the cassette. This view is also helpful in detecting subtle calcification in patients with tendonitis. The olecranon process may be better observed on the reverse axial projection ( Fig. 6-8A and B ). 1, 4, 5

FIGURE 6-7 A, Patient positioned for the axial view of the distal humerus. The elbow is flexed approximately 110 degrees, with the forearm and elbow on the cassette. The central beam (pointer) is perpendicular to the cassette and centered on the olecranon fossa. B, The radiograph provides excellent visualization of the epicondyles, ulnar sulcus, and radiocapitellar and ulnotrochlear articulations.

FIGURE 6-8 A, The patient’s arm is placed on the cassette, with the elbow completely flexed. The central beam (pointer) is perpendicular to the cassette. B, The radiograph demonstrates the olecranon, trochlea, and medial epicondyle. Contrast this view with that of Figure 6-7B .
Other views of the elbow also may be used, 1, 4, 5 but those just discussed are usually sufficient. In fact, when questions arise regarding routine AP, lateral, and oblique views, a CT scan with reformatting in the coronal and sagittal planes or an MRI scan is frequently obtained instead of special views.

ASSESSMENT OF RADIOGRAPHS/COMPUTED RADIOGRAPHY IMAGES
Assessment of the above-mentioned views should be complete and systematic. Certain findings should be checked consistently and, if necessary, further views or techniques employed.
The relationship of the radial head to the capitellum should be constant regardless of the view obtained ( Fig. 6-9A-C ). 5, 26, 28 The radius is normally bowed at the level of the tubercle. Therefore, the line should be drawn in the midpoint of the radial head, not extended to include this portion of the radial shaft.

FIGURE 6-9 The radiocapitellar relationship is constant regardless of the view. Oblique views ( A and B ) demonstrating the constant relationship of the radial head ( line ) to the capitellum ( broken circle ). Poorly positioned lateral view ( C ) with a normal radiocapitellar relationship. Positive fat pad ( arrowheads ) sign due to a subtle fracture.
Careful evaluation of the fat pads and supinator fat stripe is essential. These structures are best observed on the lateral (see Fig. 6-2 ) and radial head (see Fig. 6-6 ) views. The anterior and posterior fat pads are intracapsular but extrasynovial. 5, 8, 10, 26, 28 The anterior fat pad is normally visible on the lateral view. The posterior fat pad is obscured owing to its position in the olecranon fossa ( Fig. 6-10 ). Displacement of the fat pads, particularly the posterior fat pad, is indicative of an intra-articular fluid collection due to inflammation or hemarthrosis due to trauma. 5, 8, 10, 26, 28 Norell 26 reportedthat 90% of children with displaced posterior fat pads had elbow fractures. This finding is less specific in adults, but if present in patients following trauma (see Fig. 6-9C ), a fracture is likely. Cross-table lateral views may be more specific. A lipohemarthrosis, which is more specific for an intra-articular fracture, may be evident. 5, 26, 28

FIGURE 6-10 Lateral illustration of the elbow, demonstrating the anterior and posterior fat pads. These structures are intracapsular but extrasynovial.
The supinator fat stripe lies anterior to the radial head and neck on the surface of the supinator muscle. Fractures of the elbow frequently displace or obliterate this structure, providing a clue to the underlying injury ( Fig. 6-11 ). Rogers and MacEwan 28 reported changes in the fat stripe in 100% of fractures of the radial head and neck and in 82% of other elbow fractures.

FIGURE 6-11 Anteroposterior ( A ) and lateral ( B ) radiographs of the elbow, demonstrating displacement of the fat pads ( arrows ) and supinator fat stripe ( open arrow ) due to a subtle impacted radial neck fracture.
The anterior humeral line helps detect subtle supracondylar fractures in children but is not used as frequently for adults. This line, drawn along the anterior humeral cortex, should pass through the middle third of the capitellum ( Fig. 6-12 ). 5

FIGURE 6-12 Lateral view of the elbow in a child with a displaced physeal fracture of the distal humerus. The anterior humeral line passes through the posterior capitellum. Note the fat pads ( small arrows ) are displaced.

STRESS VIEWS
In patients with suspected ligament disruption or instability, varus and valgus stress views are desirable and may be diagnostic. Ideally, these examinations should be performed with fluoroscopic guidance. This allows proper positioning of the elbows. Also, visualization of subtle changes in the articular distance may be evident while stress is being applied. Fluoroscopic images should be obtained in the neutral position and during valgus and varus stress. Accuracy may be hindered by guarding and swelling following acute injury. In this situation, anesthetic injection should be performed before the examination. In the normal elbow, the joint should not open when stress is applied. We have arbitrarily chosen an increase in the joint space of greater than 2 mm as being abnormal ( Fig. 6-13A and B ). The relationship of the tip of the olecranon in the fossa is also helpful in interpreting radiographic instability. The normal elbow carrying angle also may increase significantly if ligament instability is present. 5

FIGURE 6-13 Anteroposterior views of the elbow in neural ( A ) and valgus ( B ) stress. Note that the joint space ( lines ) has increased ( arrow ), indicating the presence of a ligamentous injury.

COMPUTED TOMOGRAPHY
Conventional tomography is rarely performed today due to the improved utility of CT and new fast multi detector CT systems. CT is useful in the evaluation of bone and soft tissue abnormalities. 5, 19 Articular deformities, complex fractures with multiple fragments and other conditions can be evaluated quickly and reformatted into coronal and sagittal planes. Three-dimensional reconstructions can also be obtained. Thin sections using 0.5- to 1.0-mm slices can be easily reconstructed ( Fig. 6-14A and B ). 19 We frequently use CT in combination with arthrography to more clearly define articular or capsular abnormalities. 5, 30

FIGURE 6-14 Coronal ( A ) and sagittal ( B ) reformatted CT images after elbow trauma demonstrating radial head fractures (arrowheads) and a distal humeral avulsion (open arrow).

ARTHROGRAPHY
Elbow arthrography provides valuable information about capsule size, the synovial lining, supporting ligaments, and the articular surfaces of the joints. Needle access also permits fluid aspiration for laboratory studies and diagnostic or therapeutic injections. 6 The most common indications for this procedure are the detection of possible loose bodies, evaluation of articular cartilage, and the demonstration of capsular/ligament injuries. Loose bodies may be osteocartilaginous, owing to osteochon dromatosis or osteochondral fragments due to acute trauma, or osteochondritis dissecans. Less commonly, arthrograms are performed to evaluate capsule size in patients with adhesive capsulitis. 5, 7, 12, 14, 20, 32

TECHNIQUE
To obtain maximum information, arthrography should be performed by an experienced physician with a thorough understanding of the patient’s clinical situation. Review of the routine radiographs or CR images is essential. These images often provide clues that dictate subtle changes that indicate which imaging technique (conventional, CT, MRI) should be employed following the injection of the contrast material. The choice of contrast material and indications for conventional, CT, or MR arthrography are highly dependent on the clinical setting ( Table 6-1 ). 7, 31
TABLE 6-1 Elbow Arthrography: Indications and Techniques Indication Technique
Loose bodies
Osteochondromatosis
Osteochondritis dissecans Conventional or CT arthrography Fracture fragments from acute trauma CT arthrography Ligament and capsule tears MR arthrography Synovitis Indirect or intravenous MR arthrogram with gadolinium Synovial cysts MR arthrography Articular cartilage abnormalities MR or CT arthrography Capsule size Conventional arthrography Needle position before aspiration or diagnostic/therapeutic injection Conventional arthrography
Postoperative
Total joint replacement
Other
Subtraction technique for total elbow arthroplasty
Conventional arthrography with subtraction technique
CT, computed tomography; MR, magnetic resonance.
Contrast agents include air, iodinated contrast material, or a combination of the two for conventional or CT arthrography and gadolinium diluted in iodinated contrast and anesthetic for MR arthrography. Radiographs or CR images are obtained immediately following injection of contrast medium to avoid dilution thatreduces image quality. CT and MR arthrography should be performed within 30 and 45 minutes following injection, respectively. If longer delays are expected, this dilutional phenomenon can be prevented by combining 0.3 mL of 1:1000 epinephrine with the contrast agent. 5, 7, 31, 32
The procedure can be performed with the patient positioned either sitting adjacent to the radiographic table or lying prone on the table ( Fig. 6-15 ). Determination of the best position depends on the equipment available and the patient’s condition. In either position, the elbow is flexed 90 degrees, with the lateral aspect toward the examiner. Before the injection of contrast agent, fluoroscopic evaluation of range of motion and evidence of possible ligament stability or loose bodies should be accomplished. 5

FIGURE 6-15 Patient positioned for lateral injection ( A ) and posterior injection ( B ), sitting with the elbow flexed and the metal marker over the needle entry sites. Patient positioned prone ( C ) for radiocapitellar injection.
The elbow is then prepared using sterile technique. One of two injection sites may be used. In most cases, a lateral approach into the radiocapitellar joint is selected. In patients with previous radial head resection or suspected lateral ligament injury, a posterior approach is more suitable. With the posterior approach, the elbow is again flexed 90 degrees, and the medial and lateral epicondyles and olecranon are palpated. The needle is placed an equal distance between these points and is positioned fluoroscopically ( Fig. 6-16 ). If the needle is properly positioned, the contrast medium will flow away from the needle tip as it is injected. If the needle is not properly positioned, the contrast agent collects at the needle tip and significant resistance is encountered.

FIGURE 6-16 Illustration of needle positioned for lateral ( A ) and posterior ( B ) approaches.
Following the injection, the needle is removed and the elbow is studied fluoroscopically. This step is essential in evaluating stability of the joint and loose bodies. Routine films or CR images include AP, lateral, and both oblique views. Medial and lateral cross-table lateral views provide additional information with double contrast technique. 5, 32 CT images are obtained using thin sections (1 mm) with reformatting in the coronal and sagittal planes. MRI scans are also obtained in the axial, coronal, and sagittal planes with fat-suppressed T1-weighted images and at least one T2-weighted series as periarticular cysts may not communicate with the joint. 7, 31

NORMAL FINDINGS
In the normal conventional arthrogram ( Fig. 6-17A-D ), the radiocapitellar, ulnotrochlear, and radioulnar joints can be identified. The anterior (coronoid), posterior (olecranon), and annular recesses also are visualized.

FIGURE 6-17 Routine projections for single contrast arthrogram with normal anatomy labeled. A, Anteroposterior view. B, Lateral view. C and D, Oblique views.
The normal joint capacity is 10 to 12 mL. This may increase to 18 to 22 mL in patients with chronic instability, or it may be decreased in patients with capsulitis or flexion contracture. 5

ABNORMAL FINDINGS
“Loose bodies” may be either attached to the synovium or actually free within the joint. If they are free, they can be observed fluoroscopically or demonstrated on images by contrast that completely surrounds the structure ( Fig. 6-18 ). 5, 7, 31 Differentiation of a loose body in the olecranon fossa from the normal os supratrochlear dorsale is possible because of the nature of the trabecular pattern and the cortical thickness. Most symptomatic densities in the olecranon fossa have prominent trabeculae and sclerotic cortical margins ( Fig. 6-19B ). The normal ossicle has sparse trabeculae and a thin cortical rim (see Fig. 6-19A ). 5, 27

FIGURE 6-18 Single-contrast conventional arthrogram image. The contrast medium completely surrounds the lucent loose body (arrow) in the olecranon fossa.

FIGURE 6-19 Lateral tomograms of the elbow. A, Asymptomatic patient with an os supratrochlear dorsale. Note the thin cortex and lack of trabeculae ( arrow ). B, Symptomatic patient with a density in the same region with thick cortex (large arrow) representing a loose body. There is a second smaller density in the joint space inferiorly.
MR arthrography is preferred to exclude ligament/capsular tears, although conventional techniques may demonstrate the tear when they are complete ( Figs. 6-20 and 6-21 ). Extravasation of contrast material on conventional images indicates a tear (see Fig. 6-20 ). Care must be taken not to mistake extravasation at the needle site for a rent of the capsule. Therefore, the needle should not be placed near the area of suspected injury regardless of the imaging technique selected. If a lateral tear is suspected, a posterior approach should be used. 5

FIGURE 6-20 Elbow arthrogram in a patient with ligament and capsular tear with contrast extravasation medially.

FIGURE 6-21 Coronal fat suppressed T2-weighted MR arthrogram demonstrates a complete tear of the radial collateral ligament (arrow).

COMPLICATIONS
Complications due to elbow arthrography are rare. Freiberger 13 reports an incidence of infection of approximately 1 in 25,000 cases. Effusions may occur whether contrast material or air is used; they usually occur within 12 hours and may result in pain and joint stiffness. 5, 13, 31 The joint fluid may have a turbid appearance owing to the high eosinophil count. 5
The patient should be questioned about possible allergy to the contrast medium (iodinated or gadolinium). Although it is rare (0.1% of patients affected), 13 this complication must be kept in mind. Urticaria is the most common reaction experienced, and often no treatment is necessary. In more severe cases, antihistamines may be required. Most allergic reactions occur in the first 30 minutes after the injection. Premedication with an antihistamine may be used in patients with suspected allergy. These patients should be observed for 1 or 2 hours following the procedure.

MAGNETIC RESONANCE IMAGING
MRI of the elbow can clearly define numerous types of osseous and soft tissue pathology. Improved soft tissue contrast and numerous image planes provide advantages over CT and other imaging techniques. 7, 31 Intra-articular contrast injection using gadolinium, as described previously, affords advantages provided with conventional arthrography and additional information regarding subtle synovial and cartilage abnormalities. Intravenous gadolinium is useful for detection of early synovial inflammation and enhancement of other lesions such as osteomyelitis and neoplasms. 2, 5, 7
Surface coils generally are used to improve image quality. For patient comfort, the arm should be placed at the side when possible. When the arm is raised above the head, there is often motion artifact resulting in image degradation. 5, 7
MR pulse sequences are designed to demonstrate contrast differences between normal and abnormal tissues. Multiple pulse sequences and image planes are required to identify and stage pathology. Often, the axial plane is combined with sagittal ( Fig. 6-22 ) or coronal images for initial screening. 5, 7 In certain situations, new fast-scan techniques are used to allow motion (pronation-supination or flexion-extension) studies to be performed. Pronation-supination maneuvers ( Fig. 6-23 ) are most easily performed, because MR gantry size limits ranges of flexion and extension. Newer open magnets provide more flexibility for motion. 7

FIGURE 6-22 Patient with chronic muscle pain and weakness. ( A ) Oblique view of the elbow shows several areas of soft tissue ossification or avulsed fragments laterally ( arrowheads ). Coronal ( B ) and axial ( C ) T1-weighted images (SE 500/11) show low signal intensity changes in the fat and muscle ( B ) ( arrows ). Axial ( D ) and coronal ( E ) T2-weighted images demonstrate increased signal intensity in the muscles due to a muscle tear.

FIGURE 6-23 Sagittal gradient echo images in different degrees of supination. A, The biceps tendon (arrow) is in the image plane. B, The tendon is snapping over the ganglion (arrows).

ULTRASONOGRAPHY
Ultrasound applications for musculoskeletal imaging have expanded dramatically from the late 1970s. Improved technology and image quality permit more accurate depiction of normal anatomy and pathologic lesions. Ultrasonography is also more readily available and less expensive than MRI. 5, 21, 24, 25
Ultrasound uses mechanical vibrations whose frequencies are beyond audible human perception (about 20,000 Hz or cycles per second). Imaging of most musculoskeletal structures is accomplished in the 7- to 12-MHz range. 21, 24 Doppler ultrasonography for peripheral vascular studies is performed in the 8-MHz range. 25 New Doppler scanners provide color flow data that allow different flow rates (venous, arterial) to be easily demonstrated. 5, 25
The central component of ultrasound instruments is the transducer, which contains a piezoelectric crystal. The transducer serves as a transmitter and receiver of sound waves. By applying the vibrating transducer to the skin surface (through an acoustic coupling medium such as mineral oil or gel), the mechanical energy is transmitted into the underlying tissues as a brief pulse of high-energy sound waves. Sound waves reach different tissue interfaces (acoustic impedances), resulting in reflection or refraction. The reflected sound waves return to the transducer, where they are converted into electrical energy used to produce the image. 5, 21, 24, 25
Ultrasound, once limited to evaluating solid and cystic soft tissue lesions, is now commonly employed to evaluate articular and periarticular abnormalities. In the elbow, ultrasonography is well suited for evaluating tendon ( Fig. 6-24 ) and nerve ( Fig. 6-25 ) pathology. Tendon tears are demonstrated as gaps or areas of abnormal echo texture compared with the normal tendon (see Fig. 6-24 ). Avulsed bone fragments or calcifications are hyperechoic with posterior acoustic shadowing. 21 Cost and flexibility of this technique will, no doubt, result in increased orthopedic use. 24

FIGURE 6-24 Longitudinal ultrasonographic image of a normal ( right ) and ruptured (left) tendon.

FIGURE 6-25 Ultrasound of ulnar nerve dislocation demonstrated on pre- ( A ), passive ( B ) and active ( C ) resistance.
(Courtesy of Gina Hesley, Mayo Clinic, Rochester, Minnesota.)

RADIONUCLIDE SCANS/POSITRON EMISSION TOMOGRAPHY
There are numerous isotopes and indications for radionuclide imaging of the musculoskeletal system. 5 Bone scans are typically obtained after intravenous injection of 10 to 20 mCi (370-740 MBq) of technetium-99m–labeled methylene diphosphonate. Images are obtained 2 to 4 hours after injection. Common indications include primary or metastatic bone lesions, subtle fractures, non-accidental trauma in children and other causes of suspected osseous related pain. 5
Three-phase bone scans use the same isotope and dose, but images are obtained in the initial 60 seconds after injection, followed by blood pool images at 2 to 5 minutes and delayed images at 3 to 4 hours. Indications for three phase scans include differentiation of cellulitis from osteomyelitis, bone infarction, reflex sympathetic dystrophy, and peripheral vascular disease. 5, 29
Bone marrow scintigraphy is performed using 10 to 15 mCi (370-555MBq) of technetium-labeled sulfur colloid. Images are obtained approximately 15 minutes after injection. Lead shields are placed over the abdomen to delete counts from the liver and spleen. Bone marrow imaging is most often performed to evaluate marrow replacement disorders and patients with joint prostheses. 5
Special approaches may be required in patients with suspected infection. A normal bone scan or three-phase bone scan virtually excludes the possibility of infection. These techniques are sensitive but not specific. Therefore, when there is a high index of suspicion, more specific approaches are generally employed. White blood cells labeled with indium-111 or technetium or technetium-labeled antigranulocyte antibodies provide more specificity. 15, 22
Indium-111-labeled leukocyte scans are performed 18 to 24 hours after intravenous injection of the isotope. Technetium-labeled leukocytes or antigranulocyte antibody imaging is performed 2 to 4 hours after injection. Technetium is more readily available, and image resolution is superior to Indium-111 studies. Gallium-67 citrate scans can also be used to identify infection. Scanning is performed 24 to 72 hours after injection. This isotope is less commonly used today. 9 Combined studies (i.e., technetium and white blood cells or indium-111 and technetium sulfur colloid) may be required in chronic infections or in the presence of orthopedic implants or prostheses. 5, 9, 22
Positron emission tomography (PET) has provided a new physiologic approach to imaging musculoskeletal disorders, specifically infection and neoplasms. 11, 18 Positron-emitting agents include flourine-18-deoxyglucose, L-methyl-carbon 11, and oxygen 15. Flourine-18 has a half life of 110 minutes compared with the shorter half life of 20 and 21 minutes respectively for the other agents. Therefore, flourine-18 is the clinical agent of choice. Flourine-18-deoxyglucose imaging demonstrates increased glucose use seen with active disease processes. Patients must be fasting for 4 hours before the study. No sugared beverages should be taken, and blood sugar should be normal for optimal studies. Scanning is performed 1 hour after injection. Early studies demonstrate that PET imaging is more accurate than the studies described above for evaluating infection, chronic infection, and infection associated with orthopedic fixation devices or arthroplasty. PET is also more useful than conventional isotopes for detection of tumor activity and metastasis. 11, 18

References

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2 Beltran J., Chandnani V., McGhee R.A. Gadopentatate dimeglumine-enhanced MR imaging of the musculoskeletal system. A. J. R . 1991;156:457.
3 Berland L.L., Smith K.L. Multi-detector array CT. Once again new technology creates new opportunities. Radiology . 1998;209:327.
4 Bernau A., Berquist T.H. Positioning Techniques in Orthopedic Radiology. Orthopedic Positioning in Diagnostic Radiology. Baltimore: Urban and Schwartzenberg, 1983.
5 Berquist T.H. Imaging of Orthopedic Trauma, 2nd ed. New York: Lippincott-Raven Press, 1992.
6 Berquist T.H. Diagnostic/therapeutic injections as an aid to musculoskeletal diagnosis. Semin. Intervent. Radiol . 1993;10:326.
7 Berquist T.H. MRI of the Musculoskeletal System, 5th ed. Philadelphia: Lippincott-Williams and Wilkins, 2006.
8 Bohrer S.P. The fat pad sign following elbow trauma. Clin. Radiol . 1970;21:90.
9 Boutin R.D., Joachim B., Sartoris D.J., Reilly D., Resnick D. Update of imaging of orthopedic infections. Orthop. Clin. North Am . 1998;29:41.
10 Corbett R.H. Displaced fat pads in trauma to the elbow. Injury . 1978;9:297-298.
11 De Winter F., Van de Wiele C., Vogelaers D., de Smet K., Verdonk R., Dierckx R.A. Flourine-18 fluorodeoxyglucose-positron emission tomography. A highly accurate imaging modality for diagnosis of chronic musculoskeletal infections. J. Bone Joint Surg . 2001;83A:651.
12 Eto R.T., Anderson P.W., Harley J.D. Elbow arthrography with the application of tomography. Radiology . 1975;115:283.
13 Freiberger R.H., Kaye J.J. Arthrography. New York: Appleton Century Crofts, 1979.
14 Godefroy G., Pallardy G., Chevrot A., Zenny J.C. Arthrography of the elbow: anatomical and radiological considerations and technical considerations. Radiology . 1981;62:441.
15 Gold R.H., Hawkins R.A., Katz R.D. Bacterial osteomyelitis: findings on radiography, CT, MR and scintigraphy. A. J. R . 1991;157:365.
16 Greenspan A., Norman A. The radial head, capitellar view. Another example of its usefulness. A. J. R . 1982;139:193.
17 Greenspan A., Norman A. The radial head, capitellar view. Useful technique in elbow trauma. A. J. R . 1982;138:1186-1188.
18 Guhlmann A., Brecht-Krause D., Suger G., Glatting G., Kotzerke J., Kinzl L., Reske S.N. Flourine-FDG PET and technetium-99m labeled antigranulocyte antibody scintigraphy for chronic osteomyelitis. J. Nucl. Med . 1998;39:2145.
19 Haapamaki V.V., Kiuru J.J., Koskinen S.K. Multi-detector computed tomography diagnosis of adult fractures. Acta Radiol . 2004;45:65.
20 Hudson T.M. Elbow arthrography. Radiol. Clin. North Am . 1981;19:227.
21 Jacobson J.A., van Holsbeeck M.I. Musculoskeletal ultrasonography. Orthop. Clin. North Am . 1998;29:135.
22 Kaim A., Ledermann H.P., Bongartz G., Messmer P., Müller-Brand J., Steinbrich W. Chronic post-traumatic osteomyelitis of the lower extremity: comparison of magnetic resonance imaging and combined bone scintigraphy with radio labeled monoclonal antigranulocyte antibodies. Skel. Radiol . 2000;29:378.
23 Kramer J., Hofmann S., Die M.R. Magnetic resonance arthrography: benefits and indications. Adv. M. R. I. Contrast . 1997;4:104.
24 Lin J., Fessell D.P., Jacobson J.A., Weadock W.J., Hayes C.W. An illustrated tutorial of musculoskeletal ultrasound. A. J. R . 2000;175:637.
25 Merritt C.R.B. Doppler color flow imaging. J. Clin. Ultra . 1987;15:591.
26 Norell H.G. Roentgenologic visualization of the extracapsular fat. Its importance in the diagnosis of traumatic injuries to the elbow. Acta Radiol . 1954;42:205.
27 Obermann W.R., Loose H.W.C. The os supratrochlear dorsale: a normal variant that may cause symptoms. A. J. R . 1983;141:123.
28 Rogers S.L., MacEwan D.W. Changes due to trauma in the fat plane overlying the supinator muscle: a radiographic sign. Radiology . 1969;92:954.
29 Rupani H.D., Holder L.E., Espinola D.A., Engin S.I. Three phase radionuclide bone imaging in sports medicine. Radiology . 1985;156:187.
30 Singson R.D., Feldman F., Rosenberg Z.S. The elbow joint: assessment with double contrast CT arthrography. Radiology . 1986;160:167.
31 Steinbach L.S., Palmer W.E., Schweitzer M.E. MR arthrography. RadioGraphics . 2002;22:1223.
32 Weston W.J., Dalinka M.K. Arthrography. New York: Springer Verlag, 1980.
PART III
Surgery and Rehabilitation
CHAPTER 7 Surgical Exposures of the Elbow

Bernard F. Morrey

INTRODUCTION
Few joints require familiarity with as many surgical exposures as does the elbow. Depending on the lesion and the surgical goal, the joint and the surrounding region may be approached from the lateral, posterior, medial, or anterior direction.
Exposures from the medial and lateral aspects that once allowed the removal of loose bodies and the treatment of certain localized fractures are used less commonly today. Instead, some form of an extensile posterior exposure is used for most complex fractures and joint reconstructive procedures, and this is considered the universal approach to the joint.
It is not the purpose of this chapter to discuss all of the approaches to the joint but rather to provide a comprehensive collection and critique of those relevant exposures that should prove helpful to the practicing orthopedic surgeon. 33

GENERAL PRINCIPLES
Rigorous adherence to the principles of good surgical technique is of no greater importance in any anatomic part than at the elbow. 6, 8, 35 The most appropriate surgical approach depends on the specific goal of the surgical intervention and on the lesion. As for any orthopedic procedure, the choice of the surgical approach should be based on the following criteria ( Box 7-1 ):
1. Potential to be extended to meet unforeseen circumstances.
2. Capability for providing adequate visualization to define and completely correct the problem.
3. Safety: avoidance of vital structures or visualization of these structures to avoid injury during the procedure.
4. Preservation of the normal anatomy as much as possible during the exposure, the procedure, and at closure.
5. Dissection along natural tissue planes rather than across muscle, tendon, or ligamentous structures.
6. Provision of careful hemostasis and adequate drainage after extensile exposures and dissections.
7. Careful soft tissue closure that reliably heals and ensures rapid and predictable rehabilitation.

BOX 7-1 Principles of Exposure of the Elbow Region

1. Flexible—allows extension
2. Adequate—visualization of pathology
3. Safety—especially nerves
4. Preservation—respect anatomy
5. Natural plane—extend along fascial, subcutaneous planes
6. Hemostasis—release tourniquet, drain as necessary
7. Closure—modified by specific features of case.
A thorough understanding of the anatomy of the elbow region and the relationship of the nerves and vessels is particularly important to selecting the exposure that best satisfies these requirements ( Fig. 7-1 ).

FIGURE 7-1 Cross-sectional anatomy shows the important neurovascular and muscular relationships that must be understood to achieve a complication-free exposure of the elbow.
(Modified from Eycleshymer, A. C., and Schoemaker, D. M.: A Cross Section Anatomy. New York, D. Appleton and Co., 1930. In Darrach, W.: Surgical approaches for surgery of the extremities. Am. J. Surg. 67:93, 1945.)

LATERAL APPROACHES
A lateral exposure, probably the most commonly used approach to the elbow joint, offers many variations. It is used for radial head excision, removal of loose bodies, and repair of lateral ligaments, to fix condylar and Monteggia fractures, to release the joint capsule, and to remove osteophytes. Access to the radiohumeral articulation has been described by several authors. 7, 18, 21, 24, 36 The techniques differ according to the muscle interval entered and the means of reflecting the muscle mass from the proximal ulna. With any of the lateral exposures to the joint or to the proximal radius, the surgeon must be constantly aware of the possibility of injury to the posterior interosseous or recurrent branch of the radial nerve.
Kaplan has described an approach through the interval between the extensor digitorum communis and the extensor carpi radialis longus and brevis muscles. Because of the proximity of the radial nerve, pronation of the forearm during exposure has been recommended to assist in carrying the radial nerve out of the surgical field. The effect of this maneuver has been quantified by Strachan and Ellis, who found that approximately 1 cm of mediolateral radial nerve translation can occur with forearm pronation ( Fig. 7-2 ). 42

FIGURE 7-2 Approximately 1 cm of medial to lateral translation of the posterior interosseous nerve occurs as the forearm is rotated from supination to pronation.
(Redrawn from Strachan, J. H., and Ellis, B. W.: Vulnerability of the posterior interosseous nerve during radial head resection. J. Bone Joint Surg. 53B:320, 1971.)
Even with this maneuver, however, the radial nerve is precariously close to the surgical field, so this approach is used less often than that described by Kocher. Knowledge of Kaplan’s interval 24 is useful to expose the posterior interosseous nerve when decompression is performed in conjunction with tennis elbow release (see Chapter 44 ). 41

THE KOCHER APPROACH AND ITS VARIATIONS
Some variation of the Kocher exposure is the most frequently used approach to the lateral aspect of the joint. This has the advantage of being extensile, affording a full complement of surgical options as the exposure is extended. This approach enters the joint through the interval of the anconeus and extensor carpi ulnaris, thus providing protection to the deep radial nerve. The interval is also anterior to the lateral ulnar collateral ligament, which reduces the likelihood of severing it at arthrotomy. In addition to providing a limited exposure for radial head excision and loose body removal, the particular value of this technique is that it may be converted to an extensile posterolateral approach to the entire distal humerus. If an extensile exposure is anticipated, a posterior incision is made. The same deep exposure can be accomplished by extending the posterior lateral skin incision and elevating the lateral skin cutaneous flap.

Limited Distal Lateral Approach: Kocher “J”

Indication
Simple excision of the radial head. Exposure lateral ulnar collateral ligament. 24

Landmarks
Lateral epicondyle, radial head, palpate interval between anconeus and extensor carpi ulnaris.

Skin Incision
The skin incision is made from the subcutaneous border of the ulna obliquely across the posterolateral aspect of the elbow in line with Kocher’s interval and ends at or just proximal to the lateral epicondyle ( Fig. 7-3A ).

FIGURE 7-3 The distal Kocher approach. A, The incision begins approximately 2 to 3 cm above the lateral epicondyle over the supracondylar bony ridge and extends distally and posteriorly for approximately 4 cm. B, The interval between the anconeus and the extensor carpi ulnaris is identified. C, Development of this interval reveals the capsule. The joint capsule may be entered proximal to the annular ligament (D), and a more extensive exposure may be obtained by extending the capsular incision proximally (E), thus providing adequate exposure of the radiohumeral articulation.
(Redrawn from Banks, S. W., and Laufman, H.: An Atlas of Surgical Exposures of the Extremities. Philadelphia, W. B. Saunders Co., 1953.)

Interval
The interval between the anconeus and extensor carpi ulnaris is identified and entered ( Fig. 7-3B ). For excision of the radial head, the extensor carpi ulnaris and a small portion of the supinator muscle are dissected free of the capsule and retracted anteriorly (see Fig. 7-3C ). The annular ligament is then identified and entered. Care should be taken to enter the annular ligament approximately 1 cm above the crista supinatoris to avoid injury to the lateral ulnar collateral ligament (see Fig. 7-3D ).

Expanding the Distal Lateral Exposure

Indication
Reconstruction of the lateral ulnar collateral ligament, harvest anconeus for anconeus arthroplasty. 31

Landmarks
Lateral epicondyle; posterior border of the extensor carpi ulnaris, anterior edge of anconeus, crista supernatoris of ulna.

Skin Incision
If the lateral ulnar collateral ligament is to be reconstructed, the skin incision described earlier is simply extended proximally about 3 cm.

Interval
After the interval is entered, the anconeus is more completely reflected from its ulnar insertion ( Fig. 7-4A ). The lateral collateral ligament complex is identified by first elevating the extensor carpi ulnaris from the annular ligament just distal to the lateral epicondyle (see Fig. 7-4B ). The fleshy attachment of the extensor carpi radialis longus is identified just above the common extensor tendon. This origin is freed from the supracondylar ridge. The dissection then elevates the common extensor tendon and the posterior edge of the extensor carpi radialis brevis from the lateral ligament complex (see Fig. 7-4D ). This is done very carefully to identify and leave intact the lateral collateral ligament complex, and thus, reconstruction of the lateral ulnar collateral ligament can take place (see Chapter 48 ).

FIGURE 7-4 A, The anconeus is easily reflected posteriorly from its bed to expose the crista supinatoris ( arrowheads ). B, Lifting the anterior musculature, including the common extensor tendon and the extensor carpi ulnaris, adequately exposes the lateral collateral ligament complex, allowing reconstruction of this structure.

The Limited Proximal Lateral Exposure (Column Approach)

Indication
Stiff elbow: Anteroposterior capsular release; also termed the column procedure. 28, 31

Landmarks
Extensor carpi radialis longus, lateral epicondyle, radial head, anterior capsule.

Note
This may truly be termed a minimally invasive procedure.

Skin Incision and Technique
This limited exposure of the anterior (and posterior) capsule has been described by Mansat and Morrey. 28 The skin incision is over the lateral column, extending distally over the lateral epicondyle to the radial head ( Fig. 7-5A ). The extensor carpi radialis longus and distal fibers of the brachial radialis are elevated from the lateral column and epicondyle (see Fig. 7-5B ). The brachialis muscle is separated from the anterior capsule, which can be safely performed if the joint has been entered at the radiocapitellar articulation. Since the arthrotomy provides accurate spatial orientation across the joint, damage to neurovascular structures is avoided. The procedure then continues as described in Chapter 44 .

FIGURE 7-5 A, The column procedure provides a limited exposure of the anterior capsule. The incision is approximately 3 to 4 cm and extends from the distal aspect of the origin of the brachioradialis across the radiohumeral joint and common extensor tendon. B, The distal fibers of the brachioradialis as well as the extensor carpi radialis longus are elevated from their attachment on the humerus. C, By elevating the brachioradialis a retractor can be placed behind the anterior musculature exposing the capsule. This is facilitated if an arthrotomy has been carried out. Note that the ability to access the posterior joint is readily accomplished through the so-called posterior interval which elevates the triceps attachment from the posterior aspect of the lateral supracondylar ridge.

POSTEROLATERAL EXPOSURES

THE BOYD POSTEROLATERAL EXPOSURE 7
Exposure of the lateral ulnohumeral and radiohumeral joint is accomplished with several variations of a posterolateral approach described by Boyd. Depending on the need to expose the proximal ulna or the distal humerus, these approaches can be extended and thus provide significant versatility. 40


Indications
Monteggia fractures, Mayo type II olecranon fractures.

Skin Incision
Begin the incision just posterior to the lateral epicondyle and lateral to the triceps tendon, and continue the incision distally to the lateral tip of the olecranon and then down the subcutaneous border of the ulna to the junction of its proximal and middle thirds or as necessary in order to expose the fracture ( Fig. 7-6A ).

FIGURE 7-6 The Boyd approach. A, The incision begins along the lateral border of the triceps approximately 2 to 3 cm above the epicondyle and extends distally over the lateral subcutaneous border of the ulna approximately 6 to 8 cm past the tip of the olecranon. B, The ulnar insertion of the anconeus and the origin of the supinator muscles are elevated subperiosteally. C, More distally, the subperiosteal reflection includes the abductor pollicis longus, the extensor carpi ulnaris, and the extensor pollicis longus muscles. The origin of the supinator at the crista supinatorus of the ulna is released, and the entire muscle flap is retracted radially, exposing the radiohumeral joint. D, The posterior interosseous nerve is protected in the substance of the supinator, which must be gently retracted. To extend the incision farther distal, the dorsal interosseous artery must be ligated.
(Redrawn from Crenshaw, A. H.: Surgical approaches. In Edmonson, A. S., and Crenshaw, A, H. [eds]: Campbell’s Operative Orthopaedics, 6th ed. St. Louis, C. V. Mosby, 1980. A and B modified from Boyd, H. B.: Surgical exposure of the ulna and proximal third of the radius through one incision. Surg. Gynecol. Obstet. 71:86, 1940; D modified from Eycleshymer, A. C., and Schoemaker, D. M.: A Cross Section Anatomy. New York, D. Appleton and Co., 1930.)

Technique
The anconeus and extensor carpi ulnaris are stripped subperiosteally from the ulna, beginning on the lateral subcutaneous crest of the bone and reflecting the muscles volarward. The supinator is released subperiosteally from its ulnar insertion, and the entire muscle mass is reflected anteriorly (see Fig. 7-6B ). Be careful not to detach the ulnar attachment of the lateral ulnar collateral ligament. Thus, the lateral surface of the ulna and the proximal portion of the radius are adequately exposed (see Fig. 7-6C ). The substance of the reflected supinator protects the deep branch of the radial nerve (see Fig. 7-6D ). If greater exposure of the radius is desired, the recurrent interosseous artery (not the dorsal interosseous artery) is divided in the proximal portion of the wound, and the muscle mass is further reflected volarward to expose the interosseous membrane. The deep branch of the radial nerve remains protected.

EXTENSILE POSTEROLATERAL EXPOSURE (KOCHER)
This is an extension of the limited exposures described above involving the release of collateral ligament and capsule. 24


Indications
Extensile exposure to the joint surface for reconstructive procedures including open reduction internal fixation, total elbow arthroplasty (resurfacing), and interposition arthroplasty.

Landmarks
Proximal: lateral column; distal Kocher interval.

Skin Incision and Technique
The triceps may be elevated from the posterior aspect of humerus by extending the skin incision proximally up the lateral column ( Fig. 7-7A ). This may proceed 6 to 7 cm proximal to the lateral epicondyle without fear of violence to the radial nerve.

FIGURE 7-7 A, The incision is made 8 cm proximal to the joint just posterior to the supracondylar bony ridge and extending distally over the anconeus for approximately 6 cm. B, The interval between the anconeus and the extensor carpi ulnaris is identified and entered. C, The anconeus is reflected subperiosteally from the proximal ulna along with its fascial attachment to the triceps, which is likewise reflected medially, exposing the supinator muscle. The insertion of the triceps on the tip of the olecranon is released by sharp dissection, and the supinator muscle is released from the proximal portion of the ulna and the humerus as necessary to expose the capsule, which is entered via a longitudinal incision. D, The release of the radiocollateral ligament at its humeral origin allows joint subluxation to expose the entire distal humerus.
Proceed as shown in Figure 7-7B by completely elevating the anconeus from the ulna. The triceps is easily elevated from the posterior humerus in the normal situation, and even in post-traumatic contractures, the triceps can be elevated with a periosteal elevator without much additional difficulty (see Fig. 7-7C ). The lateral collateral ligament is released from the humeral origin as a separate structure or if prior surgery has caused scarring, with the common extensor tendon complex. The anterior capsule is then incised. A varus stress is applied to the elbow, which opens like a book hinging on the medial ulnar collateral ligament and common flexor muscles (see Fig. 7-7D ). The triceps remains attached to the ulna.

MAYO MODIFIED KOCHER EXTENSILE POSTEROLATERAL EXPOSURE


Essential Characteristic
The triceps attachment is further released from the olecranon and the triceps mechanism is reflected from lateral to medial ( Fig. 7-8A ).

FIGURE 7-8 The triceps attachment to the tip of the olecranon may be released by sharp dissection (A), allowing complete translation of the extensor mechanism medially and providing more extensile exposure to the joint (B) .

Indications
Ankylosis release, resurfacing arthroplasty, open reduction with internal fixation (ORIF), lateral column, distal humerus.

Landmarks
Triceps insertion at olecranon.

Technique
If more extensile exposure is required than has been obtained with the previous steps (see Figs. 7-5 and 7-6 ), a medial skin flap is elevated and the ulnar nerve identified. It is protected or translocated according to the merits of the case and after the release has proceeded according to the steps shown in Figure 7-6 . The triceps and anconeus muscle sleeve is reflected from the tip of the olecranon by releasing Sharpey’s fibers (see Fig. 7-8A ). The entire extensor mechanism including anconeus is thus reflected from lateral to medial (see Fig. 7-8B ). After the triceps has been reflected and the posterior capsule released, the lateral collateral ligament may be detached from the humerus depending on the goal of the specific procedure and the additional exposure required. By flexing the elbow and removing the tip of the olecranon, the articular surface and the entire posterior humerus can be exposed.

Note
We have found that the described surgical exposures to the elbow are sufficient to perform virtually all of the reconstructive procedures we currently employ. All may be executed after a posterior skin incision. The surgeon should be aware that the classic extensile approach described by Kocher does imply that the anterior capsule has been incised and the lateral collateral ligament has been released. When the Mayo modified Kocher release has been performed, the ulnar nerve must be exposed and released as necessary to avoid compression with varus angular forearm manipulation.

POSTERIOR EXPOSURES
Extensile posterior exposure implies effective management of the triceps mechanism. 5, 37 In recent years, there has been a marked increased interest in revisiting and modifying previously described posterior surgical approaches.
A posterior exposure of the elbow joint may be used for virtually any surgical indication. In fact, a posterior skin incision is now considered to be the universal approach to any deep structure of the elbow. Because the dissection may be readily extended and tissues mobilized medially and laterally, distal humeral and proximal ulnar fractures, joint reconstruction, tumors, infections, and synovial processes are amenable to treatment through a posterior exposure.
Several skin incisions and techniques have been described. Although MacAusland 27 used a transverse incision, most posterior skin incisions are longitudinal. The S incision of Ollier today is not as often used as the straighter incision recommended by Langenbeck. 25 Probably the most important aspect of any incision is that it should not cross the tip of the olecranon. Smith also attributed better healing to a medial incision as compared with a lateral one. 38
Releasing the triceps transverse section of the triceps mechanism at its musculotendinous junction has been described but does not afford adequate repair for optimal rehabilitation. 46 Releasing the triceps at its attachment to the olecranon 26 is not advisable, owing to the difficulty of adequate repair and possible disruption during rehabilitation. 9 Today we categorize triceps management into four categories: (1) triceps splitting, (2) triceps reflecting, (3) triceps preserving, and (4) olecranon osteotomy ( Fig. 7-9 ). A midline splitting incision was described as early as 1918 by James Thompson to expose the distal humerus for fractures, but it did not include release from the ulna to provide exposure of the joint itself. 44

FIGURE 7-9 The posterior approach to the elbow may be some form of triceps approach that splits (A) or releases (B) the tendon in continuity with or without a fleck of bone by preserving the triceps tendon attachment (C) or by intra-articular (D), extra-articular oblique osteotomy (E), or chevron (F) .
Splitting the triceps in line with the muscle fibers and at its insertion to expose the humerus and the elbow joint was described by Langenback 25 and Campbell. 10 This approach has had considerable resurgence of interest in recent years. When contracture is present, Campbell first separated the tendon from the muscle as an inverted V and then released the muscle fibers longitudinally. This technique, recommended later by Van Gorder 46 for distal humerus fractures, allows lengthening of the musculotendinous unit, which may be necessary to fully mobilize the ankylosed joint. This triceps torque exposure has also faced a renewed interest and popularity in recent years.

POSTERIOR TRICEPS SPLITTING (CAMPBELL) 10


Indications
Elbow arthroplasty, 1 unreduced elbow dislocation, distal humeral fracture, posterior exposure of the joint for ankylosis, sepsis, synovectomy, and ulnohumeral arthroplasty.

Note
When releasing the triceps attachment from the medial attachment at the olecranon, care must be exercised to maintain continuity of the triceps expansion with the forearm fascia in continuity with the flexor attachment. Laterally, the anconeus and triceps form a more stable composite structure that has less chance of disruption with reflection of the lateral attachment.

Technique
The skin incision begins in the midline over the triceps, approximately 10 cm above the joint line, curves gently laterally or medially at the tip of the olecranon, and continues distally over the lateral aspect of the subcutaneous border of the proximal ulna for a distance of approximately 5 to 6 cm. If the incision is curved medially at the olecranon, the scar may have less tendency to contract. 38
The triceps is exposed along with the proximal 6 cm of the ulna. A midline incision is made through the triceps, fascia, and tendon and is continued distally across the insertion of the triceps tendon at the tip of the olecranon and down the subcutaneous crest of the ulna ( Fig. 7-10 ). The muscle is elevated medially and laterally exposing the distal humerus. Sharp dissection releases the triceps and the anconeus, which are reflected subperiosteally laterally. The insertion of the triceps is carefully released from the medial olecranon, leaving the flexor mechanism in continuity with the forearm fascia. The ulnar nerve is visualized and protected in the cubital tunnel. Only closure of the triceps fascia is required proximally, but the triceps insertion may be supplemented with a suture passed through the tip of the olecranon. The incision is then closed in layers.

FIGURE 7-10 The Campbell posterior approach. The original description calls for a curved incision, but we prefer a straight one just lateral to the tip of the olecranon and the subcutaneous border of the ulna. The triceps may be released from its attachment to the ulna by a thin osteotomy at its site of attachment.
(Redrawn from Anson, B. J., and Maddock, W. G.: Callander’s Surgical Anatomy, 4th ed. Philadelphia, W. B. Saunders Co., 1958.)

Triceps Release at Osseous Attachment (Gschwend)
Gschwend modified the triceps splitting technique by osteotomizing the triceps attachment with flecks of bone medially and laterally. Closure is with circumferential sutures placed through drill holes in the ulna.

TRICEPS SPLITTING, REFLECTION OF TRICEPS APONEUROSIS


Indications
Same as those for the midline-splitting approach described earlier, plus elbow contracture and unreduced elbow dislocations (see Chapter 30 ). 10, 47

Note
This approach allows lengthening of the triceps mechanism. It has also become more popular for primary elbow replacement in recent years.

Technique
The skin incision is begun 10 cm proximal to the olecranon and extends over the lateral aspect of the proximal ulna, ending 4 cm distal to the joint ( Fig. 7-11 ). The triceps fascia and aponeurosis are isolated along with the tendinous insertion into the ulna. The aponeurosis is elevated and reflected from the muscle from proximal to distal, freeing the underlying muscle fibers while preserving the tendinous attachment to the olecranon. Proximally, the triceps muscle is then split in the midline, and the distal humerus is exposed subperiosteally. The dissection continues distally to the olecranon fossa, exposing the posterior aspect of the joint. If more extensive exposure is desired, the subperiosteal dissection is extended to the level of the joint, exposing the condyles both medially and laterally. The ulnar nerve should be identified and protected.

FIGURE 7-11 The Campbell (Van Gorder) aponeurosis turn-down approach. The triceps aponeurosis is identified and reflected distally. The remaining fibers of the triceps are then split in the midline and reflected from the humerus, and the anconeus is reflected subperiosteally from the ulna to expose the joint.
(Redrawn from Campbell, W. C., Edmonson, A. S., and Crenshaw, A. H. (eds.): Campbell’s Operative Orthopedics. In Surgical Approaches, 5th ed., Vol. I. St. Louis, C. V. Mosby Co., 1971, p. 119.)
After the procedure, if an elbow contracture has been corrected, the joint should be flexed to about 110 degrees allowing the tendon to slide distally from its initial position. The proximal muscle and tendon are reapproximated in the lengthened relationship with nonabsorbable No. 0 sutures. The distal part of the triceps is then securely sutured to the fascia of the triceps expansion with the same suture, and the remainder of the wound is closed in layers.

REFLECTION OF THE TRICEPS IN CONTINUITY
The triceps mechanism may be preserved in continuity and simply reflected to one side or the other. Three surgical approaches have been described that preserve the triceps muscle and tendon in continuity with the distal musculature and forearm fascia and expose the entire joint. These exposures were designed to allow rapid rehabilitation while limiting the risk of triceps disruption.

Mayo Modified Kocher’s Posterolateral, Extensile Triceps-Sparing Approach
This technique has been described earlier, along with the family of Kocher exposures (see Fig. 7-7 ). 23

Mayo Triceps Reflection Technique of Bryan and Morrey

Indications
Ankylosis release, semiconstrained total elbow arthroplasty, ORIF medial column, distal humerus fractures. 9

Skin Incision and Technique
A 14-cm skin incision is made just medial to the tip of the olecranon. The dissection is carried to the medial aspect of the triceps 6 cm proximal and 4 cm distal to the tip of the olecranon. The ulnar nerve is identified, and if a femoral translocation is carried out, it is released from the margin of the triceps and elevated from its bed ( Fig. 7-12A ). The cubital tunnel retinaculum is split and the nerve released to the first motor branch. A subcutaneous pocket is developed, the intermuscular septum removed (see Fig. 7-12B ), and the nerve is translocated anteriorly. The triceps is released from the entire posterior aspect of the distal humerus. Forearm fascia and ulna periosteum are elevated from the medial margin of the ulna. The Sharpey fiber attachment of the triceps to the olecranon is released by sharp dissection (see Fig. 7-12C ). The distal forearm fascia and ulnar periosteum is elevated from the ulna. The lateral margin of the proximal ulna is then identified and the anconeus is elevated from its ulnar bed (see Fig. 7-12D ). The extensor mechanism and capsule continues to be reflected from the margin of the lateral epicondyle (see Fig. 7-12E ). If a medial column fracture has occurred, the tip of the olecranon is removed and the fracture may be addressed. For semiconstrained total elbow arthroplasty, the lateral and medial collateral ligaments are released and the extensor mechanism is reflected lateral to the epicondyle. The elbow is flexed and the tip of the olecranon is removed to expose the joint (see Fig. 7-12F ).

FIGURE 7-12 The Bryan-Morrey posterior approach. A, Straight posterior skin incision (approximately 14 cm). The triceps has been exposed, as has the superficial forearm fascia originating from the medial epicondyle and olecranon. The line of incision of the distal fascia-periosteum complex is identified. B, The ulnar nerve has been translocated anteriorly into subcutaneous tissue, and the intravascular septum is removed. C, The medial border of the triceps is identified and released, and the superficial forearm fascia is sharply incised to allow reflection of the fascia and periosteum from the proximal ulna. D, The extensor mechanism has been reflected laterally, and the anconeus has been released subperiosteally from the ulna, allowing exposure of the radial head. E, The proximal portion of the olecranon is removed for joint exposure. F, The shoulder is rotated externally, and the forearm is hyperflexed. Release of the collateral ligaments allows the ulna to separate from the humerus, providing excellent exposure for replacement or interposition.
(From Bryan, R. S., and Morrey, B. F.: Extensive posterior exposure of the elbow. A triceps-sparing approach. Clin. Orthop. 116:188, 1982.)
In every instance in which the triceps has been completely reflected either from lateral to medial (see Fig. 7-7 ) or medial to lateral (see Fig. 7-12 ), it is always securely reattached to the olecranon with a locked crisscross type of suture. Drill holes about 3 cm in length are placed in a cruciate fashion in the olecranon from proximal to distal ( Fig. 7-13 ). A third transverse hole is drilled through the olecranon to secure a second stabilizing suture. The margin of the triceps is first grasped with an Allis clamp and brought over the olecranon. It is important to over correct the reattachment medially to ensure that the sleeve of tissue does not sublux laterally with flexion. A No. 5 nonabsorbable suture is introduced with a straight needle from distal to proximal for the modified Kocher and from distal medial to proximal lateral for the Mayo exposure. The suture is first brought through the osseous tunnel emerging at the tip of the olecranon and passes through the triceps tissue at its anatomic attachment site with the elbow flexed 70 degrees. The suture is locked at this site. It is then brought across the tendinous portion and locked medially. The suture then enters the medial hole in the olecranon and is passed from proximal medial to distal lateral. After the suture has emerged from the second hole in the olecranon, it is brought back over the top of the ulna through the soft tissue distal expansion of the extensor sleeve. Care is taken to leave the knot off to the side of the subcutaneous border of the ulna to avoid irritation or skin erosion. The second suture, which is very important to hold the triceps tendon securely applied to the olecranon attachment, is placed transversely across the ulna again beginning on the side from which the triceps reflection began. It is simply brought back across the triceps tendon in a transverse fashion and is locked in the midline to snugly stabilize the triceps insertion against the olecranon. All sutures are tied with the elbow in 70 to 90 degrees of flexion, again with the knots off the subcutaneous border.

FIGURE 7-13 (A) The triceps is reattached by a heavy (No. 5), nonabsorbable suture placed through crossed and transverse holes in the ulna. (B) The stitch is placed from distal to medial through the olecranon tunnel and pierces the triceps tendon at the site of attachment as the elbow is flexed to 70 degrees. (C) This stitch is locked, and a second locked stitch is placed over the medial hole in the olecranon. The stitch is brought through this hole, across the periosteal sleeve to join the free end of the suture. (D) An additional transverse suture placed from medial to lateral is locked at the center of the triceps as it overlies its attachment.
Skin closure is with staples or in some instances, a subcuticular stitch is used, particularly in women. The aftercare varies dramatically depending upon the pathology being addressed, and this is discussed in the appropriate chapter. It is worthy of note, however, that I typically splint the elbow in extension with an anterior splint for 2 to 3 days. This protects the incision and may help reduce the tendency to develop flexion contracture.

OSTEOCUTANEOUS FLAP
One variation of the Mayo approach reflects the triceps with a sliver of bone while executing the same basic exposure philosophy. 48


Indications
An extensile triceps-reflecting procedure similar in concept to the Mayo approach and most often used for joint replacement arthroplasty, it also may be used for distal humeral fractures.

Triceps Release (Wolfe and Ranawat)

Technique
The triceps attachment is released from the ulna by osteotomizing the attachment with a thin wafer of bone that continues the attachment of the triceps tendon. This is the essential difference from the Mayo approach. The medial aspect of the triceps is elevated proximally, and the triceps attachment, with the wafer of bone, is elevated from the lateral aspect of the ulna in continuity with the anconeus muscle and the fascia (see Fig. 7-12 ).
After the surgical procedure, the olecranon osteotomy is secured to its bed by 20 nonabsorbable sutures placed through bone holes. Interrupted sutures are used to repair the remaining distal portion of the extensor mechanism.

Triceps-Preserving Technique
It is possible to elevate the triceps from the medial and lateral intramuscular septae while leaving the triceps attached to the olecranon. 2, 30
Several variations are included with this description.

Indications
Absence of distal humerus such as tumor resection, joint reconstruction for resection of humeral nonunion, or revision joint replacement. 30

Technique
The technique is usually used for failed reconstructive procedures, so the previous skin incision is followed when possible. Otherwise, a posterior incision is made either medial or lateral to the tip of the olecranon. Medial and lateral skin flaps are elevated with as much subcutaneous tissue and fascia as possible. The medial and lateral aspects of the triceps are identified, and the ulnar nerve is isolated unless it was previously translocated anteriorly ( Fig. 7-14A ). The distal humeral nonunion or acute fracture fragments are sharply mobilized. The lateral collateral attachment to the humerus is severed, along with the common extensor tendon (see Fig. 7-14B ). The common flexor tendon and muscle mass are elevated from the medial epicondyle along with the medial collateral ligament, and the distal segment is removed (see Fig. 7-14C ). The distal aspect of the humerus usually is buttonholed laterally to the margin of the triceps (see Fig. 7-14D ). Occasionally, the humerus is brought through the medial interval between the triceps muscle and the ulnar nerve. Regardless of the side to which the humerus is delivered, distal traction on the forearm must be avoided because it could stretch the ulnar nerve. The ulna is rotated appropriately to allow exposure to prepare and insert the ulnar component. At this point, a portion of the triceps attachment can be released to better expose the ulna (see Fig. 7-14E ).

FIGURE 7-14 A, The medial and lateral aspects of the triceps and extensor mechanism are identified along with the ulnar nerve. B, The distal humeral fracture or nonunion is sharply dissected from the lateral aspect. C, Similarly, the distal humerus is freed of its medial soft tissue attachments, including the ligaments. Partial release of the triceps, either medially or laterally, allows the forearm to be more easily displaced and rotated. D, The loose fragments, tumor, or area of nonunion is removed, and the distal humerus is exposed from the lateral aspect. E, In some circumstances, such as with long-standing valgus deformity, exposure from the medial margin of the triceps is more efficient. Note rotation of the ulna is required to identify the medullary canal.
After the implant has been inserted, the joint is articulated. There is no need to close or repair the extensor mechanism. Skin closure is routine, and motion is begun immediately and without restriction.

Comment
I have employed this exposure since 1989 in cases in which the distal humeral articulation is absent or resected. I have expanded the application, which was first used for nonunions 29 to treat acute fractures and type IV rheumatoid arthritis. Because the triceps is not detached from its insertion at the tip of the olecranon, rapid rehabilitation is possible. It is expected that complete sparing of the triceps attachment will be used more frequently in the future and that the indications will increase. The most important caution is to avoid axial traction to the ulnar nerve from forearm manipulation.

Editor’s Note
Special comment is required to place these exposures in context. In all instances, the proponent reveals excellent outcomes. Of course, what is important is to honestly decide what works for you. We developed the Bryan-Morrey exposure specifically because we experienced unreliable strength outcomes after the Campbell splint and aponeurosis take-down, as well as thin osteotomy of the triceps insertion. All of these exposures are described earlier and are all being revisited with some degree of enthusiasm. In the final analysis, do what works for you.

POSTERIOR TRANSOSSEOUS EXPOSURES
Worldwide, a transosseous approach is probably the exposure most often used, especially for distal humeral fractures. The oblique osteotomy has almost been abandoned, and the transverse osteotomy has largely been replaced by the chevron.

OBLIQUE OSTEOTOMY


Approach
Oblique osteotomy of the olecranon. 34

Indications
T or Y condylar fracture.

Technique
A 14-cm incision is made just lateral to the midline, extending past the tip of the olecranon. The insertion of the triceps tendon to the proximal ulna is carefully identified, and a 3.2-mm hole is drilled through the tip of the olecranon, centered down the medullary canal and on the insertion of the triceps tendon ( Fig. 7-15 ). The triceps attachment is then carefully isolated and osteotomized in an oblique fashion with an oscillating saw. With its attachment to the osteotomized segment, the muscle is reflected proximally. At the completion of the procedure, the osteotomized fragment is reattached with a lag screw and the wound is closed in layers.

FIGURE 7-15 The Müller posterior oblique olecranon osteotomy. The lateral margin of the triceps is identified and reflected medially to expose the distal humerus. A, The proximal ulna is predrilled for reattachment later. B, An oblique extra-articular osteotomy, including the attachment of the triceps, is made across the proximal ulna. C, The triceps with its attachment to bone is then reflected proximally, and as the elbow is flexed the entire distal humerus and elbow joint may be exposed. D, After the procedure, the triceps is reattached with a malleolar or cancellous-type screw, which provides good compression across the osteotomy site.
(Redrawn from Müller, M. E., Allgower, M., and Willenegger, H.: Manual of Internal Fixation: Technique Recommended by the AO Group. New York, Springer-Verlag, 1970.)

CHEVRON TRANSOLECRANON OSTEOTOMY


Indications
Ankylosed joints; T or Y condylar fracture. 27

Comment
The intra-articular osteotomy first described by MacAusland was originally recommended for ankylosed joints. It has been adopted by some 20 for radial head excision and synovectomy and used or modified by others 12 for T and Y condylar fractures. However, in persons with rheumatoid arthritis, this portion of the bone may be thin, and therefore, this is not a suitable exposure for total elbow arthroplasty. The chevron design markedly enhances the repair and thus allows early motion.

Technique
Originally, a transverse incision across the elbow was described for the transverse osteotomy. At the present time, a straight incision is recommended ( Fig. 7-16A ). It is made posteriorly just lateral to the midline and measures approximately 14 cm centered on the olecranon. The ulnar nerve is isolated, dissected from the cubital tunnel, and protected. A 3.2-mm drill hole crosses the proposed osteotomy site for anatomic replacement at the completion of the procedure (see Fig. 7-16B ). The joint is exposed at the midportion of the greater sigmoid notch. An apex distal chevron, or V, osteotomy initiated with the saw and completed with an osteotomy. By allowing the subchondral bone to “crack” facilitates accurate repositioning with the interdigitated surfaces. The capsular attachments, including the posterior portion of the ulnar collateral ligament, are released. The triceps tendon, along with the osteotomized portion of the olecranon, may then be retracted proximally, and by flexing the elbow joint, the tendon can be exposed (see Fig. 7-16C ). Occasionally, the radial or medial collateral ligament may be released for better exposure, but it must later be reattached to the bone to avoid instability. At the completion of the procedure, the tip of the olecranon is secured with a single cancellous screw. The elbow usually is immobilized for 2 to 3 weeks, at which time a gentle, active rehabilitation program is instituted when clinically indicated.

FIGURE 7-16 Chevron olecranon osteotomy. A, A straight incision is made just lateral to the tip of the olecranon approximately 7 cm proximal and 7 cm distal to the tip of the olecranon. The proximal ulna is predrilled with a 3.2-mm drill, and the margins of the triceps are identified. B, The triceps is released medially and laterally, while the ulnar nerve is protected. The chevron osteotomy with a distal apex is initiated with an oscillating saw and, C, the proximal portion containing the triceps tendon is retracted proximally, exposing the elbow joint.

COMBINED OSTEOTOMY PLUS TRICEPS SPLITTING
A recent report 14 has suggested the value of combining the chevron osteotomy with a triceps-splitting technique. This would seem to offer little advantage over the chevron osteotomy as described with the associated triceps reflection techniques.

ANCONEUS SPARING OLECRANON OSTEOTOMY (MAYO TECHNIQUE)



Comment
Concern with regard to transecting the anconeus attachment to the triceps has prompted the development of an olecranon osteotomy that preserves the anconeus origin and viability. The attractiveness of this exposure is that the anconeus dissection can be done very safely and quickly. This does preserve the anconeus triceps continuity in the event that a later reconstructive procedure may be necessary that uses the anconeus.

TECHNIQUE
The patient is supine with the arm across the chest. 28
The exposure is as required by the pathology. Deep exposure is at the Kocher’s interval between the extensor carpi ulnaris and anconeus.
The interval is entered and the anconeus is identified and isolated ( Fig. 7-17A ).

FIGURE 7-17 A, The anconeus interval is exposed through a mid-line incision of the distal forearm and extended laterally and distally over the anconeus. The muscle is elevated and the midportion of the lateral ulnohumeral joint identified. B, The medial ulnohumeral joint is entered as the ulnar nerve is protected, and a Chevron osteotomy as described in Figure 7-16 is completed. The olecranon and anconeus are reflected proximally.
The anconeus is elevated from its bed by sharp dissection leaving the attachment of its origin at the fascial expansion of the triceps; the mid portion of the sigmoid notch is identified laterally (see Fig. 7-17B ).
Medially, the ulnar nerve is identified, and the midportion of the articulation is exposed (see Fig. 7-17C ).
A V-shaped Chevron osteotomy is carried out as described earlier with an oscillating saw. The osteotomy is completed with an osteotome (see Fig. 7-17D ).
The osteotomized olecranon, along with the attached anconeus, is elevated proximally.
Closure consists of the standard AO reattachment of the olecranon. The anconeus is brought back to its insertion on the ulna, and the fascia over the anconeus is closed with a running 2-0 absorbable suture.



Note
The ulnar nerve does not need to be mobilized unless dictated by the pathology.

Pitfalls
Avoid osteotomy in rheumatoid arthritis because the thin olecranon compromises healing if an osteotomy is carried out. 31 The transverse osteotomy of McAusland is associated with an approximately 5% nonunion rate. 31 Although for distal humeral fractures the Chevron osteotomy may improve these results and decrease the nonunion rate, I personally have not had the clinical need to osteotomize the olecranon in the last 14 years, and osteotomy should be avoided if the olecranon is resorbed.

MEDIAL APPROACHES
There are relatively few indications for medial exposure of the elbow joint, which has been superseded by arthroscopic approaches. The transcondylar approach described independently by Molesworth and Campbell provides excellent exposure of the joint, but it involves dissection of the ulnar nerve and healing of the osteotomized epicondyle, both of which increase the complexity, and thus limit the use, of this approach. In 1969, Taylor and Scham 43 described a medial approach to the proximal ulna that was used for fractures in this region. The most valuable contribution to medial joint exposure is that described by Hotchkiss. 21 This extensile exposure provides great flexibility, particularly for exposure of the coronoid and for contracture release.

TRANSEPICONDYLAR APPROACH


Indications
Medial epicondylar fractures, loose bodies, medial lesions whose symptoms require ulnar nerve exploration, and resurfacing arthroplasty. 10, 29

Comment
This procedure was described independently by Molesworth in England and by Campbell in the United States. Because it requires osteotomy of the medial epicondyle, which causes more concern about reattachment and healing than other exposures, the indications for its use today are limited.

Technique
With the elbow flexed at 90 degrees, a medial incision is made from 5 cm above to approximately 5 cm below the elbow over the medial epicondyle. The ulnar nerve is identified, released, and retracted from the medial epicondyle, which is freed from soft tissue. It is helpful to make a longitudinal incision in the capsule just anterior to the ulnar collateral ligament and to place a periosteal elevator under the ligament as a landmark before performing the osteotomy. In this way, healing of the osteotomy restores the integrity of the ulnar collateral ligament. With a small osteotome, the epicondyle is freed and turned downward with its muscular attachments. Blunt dissection allows distal retraction of the flexor muscles, and careful technique avoids injury to the innervation of the muscle mass. The medial aspect of the coronoid process is exposed, along with the anterior and posterior capsules, which may be reflected from the humerus as necessary for additional exposure. Valgus stress hinges the joint on the lateral ligament and the remaining portions of the capsule, and provides generous exposure of virtually the entire elbow joint. Care must be taken to protect the median nerve as it passes over the anterior aspect of the joint. The epicondyle is returned to its anatomic position and secured with a small screw or with sutures placed through the bone. This step is important, because the quality of the repair affects the integrity of the ulnar collateral ligament, which is essential to the stability of the elbow joint.

EXTENSILE MEDIAL APPROACH (“OVER-THE-TOP” [HOTCHKISS])
Indications

1. Access to the coronoid and anterior osteophytes with intact radial head 22
2. Ulnar nerve exploration required
3. Need to preserve posterolateral ulnohumeral ligament complex
4. Anterior and posterior access to the joint
5. May be converted to triceps-sparing exposure of Bryan-Morrey
Limitations

1. Need for excision of heterotopic bone on the lateral side
2. Access to radial head


Technique
The patient is usually supine and supported by a hand table. It is helpful to bring the patient as far as possible onto the hand table. The patient’s head may require support, and a roll is placed under the scapula.
The skin incision can vary between the boundaries of a pure posterior skin incision and a midline medial incision. The key to this exposure is identification of the medial supracondylar ridge of the humerus, the medial intermuscular septum, the origin of the flexor pronator muscle mass, and the ulnar nerve.
The subcutaneous skin is elevated, and the medial intermuscular septum is identified. Anterior to the septum, running just on top of the fascia (and not in the subdermal tissue), the medial antebrachial cutaneous nerve is identified and protected. It is occasionally necessary to divide this nerve to gain full exposure and to adequately mobilize the ulnar nerve, especially in revision surgery. If the patient previously had surgery, the ulnar nerve should be identified proximally before the surgeon proceeds distally. If anterior transposition was performed previously, the nerve should be mobilized carefully before the operation proceeds.
The surface of the flexor pronator muscle mass origin is found by sweeping the subcutaneous tissue laterally with the medial antebrachial cutaneous nerve in this flap of subcutaneous tissue. The medial intermuscular septum is excised from the supracondylar ridge about 5 cm proximally ( Fig. 7-18A ). The ulnar nerve is protected, and the veins at the base of the septum are cauterized.

FIGURE 7-18 A, After routine medial exposure, and taking care to protect or resect the distal branches of the medial antebrachiocutaneous nerve, the surgeon identifies the intermuscular septum and excises it for approximately 5 cm. B, The pronator and a portion of the common flexor tendon are excised from the medial epicondyle, leaving a cuff of tissue on the medial epicondyle. The muscle mass is split longitudinally leaving the ulnar head of the extensor carpi ulnaris to protect the nerve. The nerve at this point has been isolated but not translocated. C, With the nerve protected, the capsule is identified, and the undersurface of the flexor pronator group is elevated from the capsule identifying the medial aspect of the brachialis muscle. D, The brachialis muscle is elevated and the entire anterior capsule is exposed. If the primary purpose is capsular release, care is taken to transect as much of the capsule as possible rather than simply releasing it. The coronoid is readily identified on completion of the capsular release. E, A posterior exposure may also be necessary; the periosteal elevator lifts the medial aspect of the triceps from the posterior aspect of the medial condyle and medial column. The ulnar nerve is translocated anteriorly.
The supracondylar ridge is located, and elevation of the anterior muscle begins with a wide Cobb elevator. Subperiosteally, all of the anterior structures of the distal humeral region are elevated enough to allow placement of a wide Bennett retractor. The median nerve and brachial vein and artery are superficial to the brachialis muscle. Once the septum is excised, the flexor pronator muscle mass should be divided parallel to the fibers, leaving approximately a 1.5-cm span of flexor carpi ulnaris tendon attached to the epicondyle (see Fig. 7-18B ). A small cuff of fibrous tissue of the origin can be left on the supracondylar ridge as the muscle is elevated. This facilitates reattachment when closing. A proximal, transverse incision in the lacertus fibrosus may also be needed to adequately mobilize this layer of muscle. The flexor pronator origin should be dissected down to the level of bone but superficial to the joint capsule. As this plane is developed, the brachialis muscle is encountered from the underside. This muscle should be kept anterior and elevated from the capsule and anterior surface of the distal humerus. Dissection of the capsule proceeds laterally and distally to separate it from the brachialis muscle (see Fig. 7-18C ).
At this point, it is helpful to feel for the coronoid process by gently flexing and extending the elbow. A deep, narrow retractor is used and, after capsular excision, the radial head and capitellum can be visualized. In the case of contracture, the capsule, once separated from the overlying brachialis and brachioradialis, can be sharply excised (see Fig. 7-18D ). The radial nerve is identified running between the brachialis and the brachioradialis. Care should be taken to stay deep to these two muscles when elevating over to the lateral side.
In a contracture release, the anteromedial portion of the capsule often requires release. To expose this area, a small narrow retractor can be inserted to pull the attached flexor carpi ulnaris medially. This affords adequate visualization and protection of the anteromedial collateral ligament.
The ulnar nerve is mobilized to permit anterior transposition with a dissection carried distally to the first motor branch to allow the nerve to rest in the anterior position without being sharply angled as it enters the flexor carpi ulnaris. With the Cobb elevator, the triceps is elevated from the posterior distal surface of the humerus (see Fig. 7-18E ). The posterior capsule can be separated from the triceps as the elevator sweeps from proximal to distal.
The flexor pronator mass should be reattached to the supracondylar ridge with nonabsorbable braided 1-0 or 0 suture through holes in bone or to the fibrous cuff, if it is adequate. After being reattached to the medial supracondylar region, the ulnar nerve should be transposed and secured with a fascial sling (or by the surgeon’s preference) to prevent posterior subluxation.

ANTERIOR EXPOSURES
Because of the vulnerability of the brachial artery and median nerve, the anterior medial approach to the elbow is not recommended ( Fig. 7-19 ). The extensile exposure described by Henry, as modified from Fiolle and Delmas, is the best known and the most useful for anterior exposure of the joint. Minor modifications of the Henry approach have been described, 22, 39 and a limited anterolateral exposure has been described by Darrach. 14

FIGURE 7-19 Because the brachial artery and median nerve occupy the anteromedial aspect of the elbow joint, an anterior medial approach to the joint is not an option.
(Redrawn from Anson, B. J., and Maddock, W. G.: Callander’s Surgical Anatomy, 4th ed. Philadelphia, W. B. Saunders, 1958.)



Approach
Extensile anterior exposure of the elbow region. 19

Indications
Anteriorly displaced fracture fragments, excision of tumors in this region, reattachment of the biceps tendon to the radial tuberosity, exploration of entrapment syndromes, and anterior capsule release for contracture.

Technique
The skin incision begins about 5 cm proximal and lateral to the flexor crease of the elbow joint and extends distally along the anterior margin of the brachioradialis muscle ( Fig. 7-20A ). Below the elbow joint, the incision turns medially to avoid crossing the flexor crease at a right angle, thus discouraging hypertrophic scar formation. The incision continues transversely to the biceps tendon and then turns distally over the medial volar aspect of the forearm, ending approximately 6 or 7 cm distal to the flexion crease. The interval between the brachioradialis laterally and the biceps and brachialis medially is identified and entered. The fascia is released distally between the brachioradialis and the pronator teres (see Fig. 7-20B ).

FIGURE 7-20 The anterior Henry approach. A, An incision is made approximately 5 cm proximal to the elbow crease on the lateral margin of the biceps tendon. It extends transversely across the joint line and curves distally over the medial aspect of the forearm. B, The interval between the brachioradialis and brachialis proximally and the biceps tendon and pronator teres in the distal portion of the wound is identified. The radial nerve is protected and retracted along with the brachialis muscle. C, The radial recurrent branches of the radial artery and its muscular branches are identified and sacrificed if more extensive exposure is required. The biceps tendon is retracted medially, along with the brachialis muscle. D, The supinator muscle is released from the anterior aspect of the radius, which is fully supinated. E, This interval may now be developed to expose the entire anterior aspect of the elbow joint, including the capitellum, the proximal radius, and the radial tuberosity.
(Redrawn from Banks, S. W., and Laufman, H.: An Atlas of Surgical Exposures of the Extremities. Philadelphia, W. B. Saunders Co., 1953.)
The interval then is entered proximally, and gentle, blunt dissection demonstrates the radial nerve coursing on the inner surface of the brachioradialis muscle. Care is taken to avoid injuring the superficial sensory branch of the radial nerve. Because the radial nerve gives off its branches laterally, it can safely be retracted with the brachioradialis muscle. At the level of the elbow joint, as the brachioradialis is retracted laterally and the pronator is gently retracted medially, the radial artery can be observed where it emerges from the medial aspect of the biceps tendon, giving off its muscular and recurrent branches in a mediolateral direction (see Fig. 7-20C ). The muscle branch is ligated, but the recurrent radial artery should be sacrificed only if the lesion warrants the more extensive exposure that can be realized with this maneuver.
The dorsal interosseous nerve enters the supinator and continues along the dorsum of the forearm distally. The dissection continues distally, exposing the supinator muscle, which covers the proximal aspect of the radius and the anterolateral aspect of the capsule. Muscle attachments to the anterior aspect of the radius and those distal to the supinator include the discrete tendinous insertion of the pronator teres and the origins of the flexor digitorum sublimis and the flexor pollicis longus. The brachialis muscle is identified, elevated, and retracted medially to expose the proximal capsule.
If more distal exposure is needed, the forearm is fully supinated, demonstrating the insertion of the supinator muscle on the proximal radius. This insertion is incised, and the supinator is subperiosteally retracted laterally (see Fig. 7-20D ). The supinator serves as protection to the deep interosseous branch of the radial nerve, but excessive retraction of the muscle should be avoided. The proximal aspect of the radius and the capitellum are thus exposed. Additional visualization may be obtained both proximally and distally, because the radial nerve has been identified and can be avoided proximally. The posterior interosseous nerve is protected distally by the supinator muscle, and the radial artery is visualized and protected medially if a more extensile exposure is required (see Fig. 7-20E ).

Note
The recurrent and muscular branches of the radial artery and vein should be ligated before the radial artery is released, to avoid hematoma formation that could cause ischemic contracture of the forearm. Retraction of the brachioradialis and the extensor carpi radialis longus and brevis muscles is facilitated if the elbow is flexed 90 degrees. This affords easier exposure of the supinator muscle. When the supinator muscle is stripped subperiosteally from the radius, the bursa between the biceps tendon and the radius is usually identified and should be entered, facilitating subperiosteal exposure of the muscle. The proximal radius is further exposed by subperiosteal dissection as the forearm is being pronated and supinated.

RESULTS
There have been limited attempts to document the efficacy of one or the other of the various types of triceps-sparing approaches. In the original description, we compared the clinical result of the Mayo approach to that of the triceps splitting or transverse release of the triceps reattachment. 9 There were no triceps disruptions after approximately 75 procedures done with the triceps being released in continuity (Mayo approach) compared with an approximately 20% complication rate when the triceps was released transversely. Wolfe and Ranawat 48 have also observed no instances of triceps insufficiency with their modification of this approach. The use of the Mayo medial exposure was also shown to have improved triceps strength after total elbow arthroplasty. 32 This manner of exposing the elbow was found to be associated with approximately 20% greater extension strength than with the Campbell (Van Gorder) type of exposure.
An additional consideration in those with rheumatoid arthritis is the thin olecranon that compromises healing if an osteotomy is carried out. 20 The transverse osteotomy of McAusland is associated with an approximately 5% nonunion rate. 31 Although for fractures the chevron osteotomy may improve these results and decrease the nonunion rate, I personally have not had the clinical need for osteotomized the olecranon in the last 20 years and this should be avoided if the olecranon has been thinned.

COMPLICATIONS
One advantage of the above-described exposures is their relative freedom from complications. Today most problems are related to the pathology rather than the surgical approach.

WOUND HEALING
Difficult ankylosis release procedures are associated with a significant amount of swelling as often occurs in patients undergoing total elbow arthroplasty. Wound healing is generally not a problem, however, and is related to the presence of prior incisions and the magnitude of the dissection as is typical for release of the stiff elbow.

INFECTION
The infection rate after total elbow arthroplasty has been reduced at our institution from a high of 11% in 1970 to approximately 3% over the last 10 years. 32 This reduction is coincident with adopting the Mayo approach to the elbow but other technique changes have occurred in this period, including using antibiotic-impregnated cement and splinting the elbow in extension.

ULNAR NERVE INJURY
Injury to the ulnar nerve appears to be more common in those instances in which the ulnar nerve is not exposed and the elbow is flexed on the medial collateral ligament such as with the classic extensile Kocher approach. 16, 45 Simply exposing the ulnar nerve, while decreasing this complication, does not completely obviate it. The theoretical disadvantage of the Mayo approach, which allows translocation of the ulnar nerve, is that this maneuver devascularizes the nerve, and the dissection itself may cause ulnar nerve irritation. Having used this particular exposure in more than 500 cases, the incidence of permanent ulnar nerve injury with motor dysfunction is less than 1%. Therefore, I am comfortable in exposing and moving the ulnar nerve in a subcutaneous pocket as an essential and integral part of the Mayo triceps-sparing approach.

RADIAL NERVE INJURY
Although posterior interosseous nerve palsy is known to occur with some approaches to the radial nerve, 21 the complication is virtually unheard of when the joint is exposed through Kocher’s interval.

TRICEPS DISRUPTION
Triceps disruption is uncommon in our experience with either the Mayo modified extensile Kocher exposure or the Mayo medial to lateral type of approach. The incidence of triceps disruption is less than 1% in our experience. If, however, the triceps should become disrupted after either of the procedures described above, if adequate tissue is present, it may be reattached as described for the primary procedure. If the remaining tissue is inadequate, triceps power is restored either by an anconeus slide or achilles tendon allograft reconstruction (see Chapter 35 ).

References

1 Albee F.H. Arthroplasty of the elbow. J. Bone Joint Surg . 1933;15:979.
2 AlonsoLlames M. Bilaterotricipital approach to the elbow. Acta Orthop. Scand . 1972;42:479.
3 Anson B.J., Maddock W.G. Callander’s Surgical Anatomy, 4th ed. Philadelphia: W. B. Saunders Co., 1958.
4 Banks S.W., Laufman H. An Atlas of Surgical Exposures of the Extremities. Philadelphia: W. B. Saunders Co., 1953.
5 Boorman R.S., Page W.T., Weldon E.J., Lippitt S., Matsen F.A.III. A triceps-on approach to semi-constrained total elbow arthroplasty. Techniques in Shoulder & Elbow Surgery . 2003;4:139.
6 Bost F.C., Schottstaedt E.R., Larsen L., Abbott L.. Surgical approaches to the elbow joint. American Academy of Orthopaedic Surgeons: Instructional Course Lectures, Vol. 10. J. W. Edwards, Ann Arbor, 1953;180.
7 Boyd H.B. Surgical exposure of the ulna and proximal third of the radius through one incision. Surg. Gynecol. Obstet . 1940;71:86.
8 Boyd H.B. Surgical approaches to the elbow joint. Instruct. Course Lect . 1947;4:147.
9 Bryan R.S., Morrey B.F. Extensive posterior exposure of the elbow: a triceps sparing approach. Clin. Orthop . 1982;166:188.
10 Campbell W.C. Incision for exposure of the elbow joint. Am. J. Surg . 1932;15:65.
11 Campbell W.C., Edmonson A.S., Crenshaw A.H., editors. Campbell’s Operative Orthopedics, 5th ed.. Surgical Approaches, Vol. I. C. V. Mosby Co., St. Louis, 1971;119.
12 Casselbaum W.H. Operative treatment of T and Y fractures of the lower end of the humerus. Am. J. Surg . 1952;83:265.
13 Crenshaw A.H. Surgical approaches. In Edmonson A.S., Crenshaw A.H., editors: Campbell’s Operative Orthopaedics , 6th ed., St. Louis: C. V. Mosby, 1980.
14 Darrach W. Surgical approaches for surgery of the extremities. Am. J. Surg . 1945;67:93.
15 Ebraheim N.A., Andreshak T.G., Yeasting R.A., Saunders R.C., Jackson W.T. Posterior extensile approach to the elbow joint and distal humerus. Orthop. Rev . 1993;22:578.
16 Ewald F.C., Jacobs M.A. Total elbow arthroplasty. Clin. Orthop . 1984;182:137.
17 Eycleshymer A.C., Schoemaker D.M. A Cross Section Anatomy. New York: D. Appleton and Co., 1930.
18 Gordon M.L. Monteggia fracture. A combined surgical approach employing a single lateral incision. Clin. Orthop . 1967;50:87.
19 Henry A.K. Extensile Exposure, 2nd ed. Baltimore: Williams & Wilkins Co., 1957.
20 Inglis A.E., Ranawat C.S., Straub L.R. Synovectomy and debridement of the elbow in rheumatoid arthritis. J. Bone Joint Surg . 1971;53A:652.
21 Kaplan E.B. Surgical approaches to the proximal end of the radius and its use in fractures of the head and neck of the radius. J. Bone Joint Surg . 1941;23:86.
22 Kasparyan N.G., Hotchkiss R.N. Dynamic skeletal fixation in the upper extremity. Hand Clin . 1997;13:643.
23 Kelly R.P., Griffin T.W. Open reduction of T condylar fractures of the humerus through an anterior approach. J. Trauma . 1969;9:901.
24 Kocher T. Textbook of Operative Surgery, 3rd ed. London: A. and C. Black, 1911.
25 Langenbeck M. Bilaterotricipital approach to the elbow. Acta Orthop. Scand . 1972;43:479. (1864): Cited by Alonso Llames
26 Lexer B. Cited by Alonso Llames, M.: Bilaterotricipital approach to the elbow. Acta Orthop. Scand. . 1972;43:479.
27 MacAusland W.R. Ankylosis of the elbow: with report of four cases treated by arthroplasty. J. A. M. A . 1915;64:312.
28 Mansat P., Morrey B.F. The column procedure: a limited lateral approach for extrinsic contracture of the elbow. J. Bone Joint Surg . 1998;80A:1603.
29 Molesworth W.H.L. Operation for complete exposure of the elbow joint. Br. J. Surg . 1930;18:303.
30 Morrey B.F. Revision total elbow arthroplasty. In: Morrey B.F., editor. Joint Replacement Arthroplasty . New York: Churchill Livingstone; 1991:345-360.
31 Morrey B.F. Surgical exposures of the elbow. In: Morrey B.F., editor. The Elbow and Its Disorders . 3rd ed. Philadelphia: W. B. Saunders Co.; 2000:109.
32 Morrey B.F., Askew L.J., An K.N. Strength function after elbow arthroplasty. Clin. Orthop . 1988;234:43.
33 Morrey B.F., Morrey M.C. Relevant surgical exposures. In Master’s Techniques in Orthopedic Surgery . Philadelphia: Lippincott, Williams & Wilkins; 2008.
34 Muller M.E., Allgower M., Willenegger H. Manual of Internal Fixation: Technique Recommended by the AO Group. New York: Springer-Verlag, 1970.
35 Ogilvie W.H. Discussion of minor injuries of the elbow joint. Proc. Roy. Soc. Med . 1929;23:306.
36 Pankovich A.M. Anconeus approach to the elbow joint and the proximal part of the radius and ulna. J. Bone Joint Surg . 1977;59A:124.
37 Schildhauer T.A., Nork S.E., Mills W.J., Henley M.B. Extensor mechanism-sparing paratricipital posterior approach to the distal humerus. J. Orthop. Trauma . 2003;17:374.
38 Smith F.M. Surgery of the Elbow, 2nd ed. Philadelphia: W. B. Saunders Co., 1972.
39 Sorrell E., Longuet Y.J. La voie transbrachiale anterieure dans la chirurgie des fractures supracondyliennes de l’humerus chez l’enfant. Rev. Orthop . 1946;32:117.
40 Speed J.S., Boyd H.B. Treatment of fractures of ulna with dislocation of head of radius (Monteggia fracture). J.A.M.A . 1940;115:1699.
41 The radial nerve. In: Spinner M., editor. Injuries to the Major Branches of Peripheral Nerves of the Forearm . 2nd ed. Philadelphia: WB Saunders; 1978:85-91.
42 Strachan J.H., Ellis B.W. Vulnerability of the posterior interosseous nerve during radial head reaction. J. Bone Joint Surg . 1971;53B:320.
43 Taylor T.K.F., Scham S.M. A posteromedial approach to the proximal end of the ulna for the internal fixation of olecranon fractures. J. Trauma . 1969;9:594.
44 Thompson J.E. Anatomical methods of approach in operations on the long bones of the extremities. Ann. Surg . 1918;68:309.
45 Trancik T., Wilde A.H., Borden L.S. Capitellocondylar elbow arthroplasty. Two to eight year experience. Clin. Orthop . 1987;112:175.
46 Van Gorder G.W. Surgical approach in old posterior dislocation of the elbow. J. Bone Joint Surg . 1932;14:127.
47 Van Gorder G.W. Surgical approach in supracondylar “T” fractures of the humerus requiring open reduction. J. Bone Joint Surg . 1940;22:278.
48 Wolfe S.W., Ranawat C.S. The osteoanconeus flap: an approach for total elbow arthroplasty. J. Bone Joint Surg . 1990;72A:684.
CHAPTER 8 General and Regional Anesthesia and Postoperative Pain Control

Terese T. Horlocker, Sandra L. Kopp, Robert L. Lennon

INTRODUCTION
Orthopaedic procedures for the elbow are well suited to regional anesthetic techniques. Continuous catheter techniques provide postoperative analgesia and allow early limb mobilization. In addition to intraoperative anesthesia, brachial plexus and peripheral nerve blocks may also be used in the treatment and prevention of reflex sympathetic dystrophy. Conversely, although the benefits of regional anesthesia in this patient population are well established, the operative site may be adjacent to neural structures, as with total elbow arthroplasty or supracondylar fractures. For example, ulnar nerve dysfunction may occur in up to 10% of patients undergoing elbow arthroplasty. 17 Early diagnosis and intervention are paramount in reducing the severity of nerve injury; assessment of neurologic function would not be possible in the presence of a regional block. Thus, the anesthetic and analgesic management are based on the patient’s evolving neurologic status (including the need for serial neurologic examinations, the anticipated rehabilitative goals, and history of side effects or interactions to systemic analgesics). Meticulous regional anesthetic technique, careful patient positioning, and serial postoperative neurologic examinations are required to reduce the incidence of neurologic dysfunction while optimizing surgical outcome.

INTRAOPERATIVE ANESTHETIC MANAGEMENT
Surgical procedures for the distal humerus, elbow, and proximal radius, and ulna are commonly performed with regional anesthetic techniques. 4 The brachial plexus may be blocked using four distinct approaches. Advances in needles, catheters, and nerve stimulator technology have facilitated the localization of neural structures and improved success rates. Selection of regional technique is dependent on the surgical site ( Table 8-1 ). For surgery on the elbow, the supraclavicular ( Fig. 8-1 ), infraclavicular, or axillary ( Fig. 8-2 ) approaches are ideal because these approaches provide adequate blockade of the lower trunk, which remains unblocked with the more proximal interscalene technique. Supraclavicular, infraclavicular, and axillary approaches to the brachial plexus are reliable and provide consistent anesthesia to the four major nerves of the brachial plexus: median, ulnar, radial, and musculocutaneous. 19 However, the small but definite risk of pneumothorax associated with supraclavicular blocks makes this approach unsuitable for outpatient procedures. Typically, pneumothorax occurs 6 to 12 hours after hospital discharge; therefore, a postoperative chest radiograph is not helpful. Although chest tube placement is advised for pneumothorax greater than 20% of lung volume, the lung may also be re-expanded with a small Teflon catheter under fluoroscopic guidance, eliminating the need for hospital admission. The infraclavicular and axillary approaches to the brachial plexus eliminate the risk of pneumothorax and reliably provide adequate anesthesia for surgery near the elbow. 14, 19 The infraclavicular approach has the added advantage of not requiring abduction during regional block, which would be painful in the presence of arm/forearm fracture. 6 The various approaches to the brachial plexus blockade may be performed before surgical incision or after postoperative upper extremity neurologic function has been determined.

TABLE 8-1 Regional Anesthetic Techniques for Elbow Surgery *

FIGURE 8-1 (A) Supraclavicular block. The interscalene groove is identified at the clavicular level, typically 1.5 to 2.0 cm posterior to the midpoint of the clavicle. Palpation of the subclavian artery at this site confirms the landmark. A 22-gauge, 4-cm needle is directed in a caudad, slightly medial and posterior direction until either a paresthesia or motor response is elicited or the first rib is encountered. If the first rib is encountered without elicitation of a paresthesia, the needle can be systematically walked anteriorly and posteriorly along the rib until the plexus or the subclavian artery is located. Location of the artery provides a useful landmark; the needle can be withdrawn and reinserted in a more posterolateral direction that usually results in a paresthesia or motor response. On localization of the brachial plexus, a total volume of 20 to 30 mL of solution. (B) The three trunks are compactly arranged at the level of the first rib.
(Redrawn from Wedel, D. J., and Horlocker, T. T.: Nerve blocks. In Miller, R. D. [ed.]: Miller’s Anesthesia, 6th ed. Philadelphia: Elsevier, 2005, p. 1685, with permission.)

FIGURE 8-2 Axillary block. The arm is abducted at right angles to the body and the axillary artery identified. Proximal needle placement and maintenance of distal digital pressure facilitate proximal spread of the local anesthetic. Several methods of identifying the brachial plexus (transarterial injection, elicitation of paresthesia or motor response) have been described, all with reportedly good results. Overall, multiple injections (identifying more than one peripheral nerve) may shorten the onset and increase the reliability of blockade.
(Redrawn from Wedel, D. J., and Horlocker, T. T.: Nerve blocks. In Miller, R. D. [ed.]: Miller’s Anesthesia, 6th ed. Philadelphia: Elsevier, 2005, p. 1685, with permission.)
Although preoperative brachial plexus block reduces the intraoperative requirement of volatile anesthetic and opioids, and in theory provides pre-emptive analgesia, postoperative evaluation of neurologic function is not possible until block resolution. In addition, few outcome studies exist comparing regional and general anesthesia specifically for surgery about the elbow. However extrapolating the results of forearm and hand procedures under single-injection brachial plexus block versus general anesthesia, a regional technique is associated with improved analgesia, reduced opioid consumption and postoperative nausea and vomiting, and early hospital dismissal. 15 Overall, there are early but no long-term benefits with a single-injection regional anesthetic technique compared with a general anesthetic. However, placement of an indwelling perineural catheter results in more substantial and lasting benefits, including avoidance of hospital admission/readmission, decreased opioid-related side effects and sleep disturbance, and improved rehabilitation. 11, 13, 20 Thus, anesthetic management of patients undergoing elbow surgery is focused on postoperative analgesia, rather than intraoperative anesthesia to improve perioperative outcomes.

POSTOPERATIVE ANALGESIA
Patients undergoing major upper extremity surgery experience substantial postoperative pain. Indeed, 30% of patients undergoing ambulatory hand and elbow surgery reported moderate to severe pain at 24 hours postoperatively. 16 Failure to provide adequate analgesia impedes early physical therapy and rapid rehabilitation, which are important for maintaining joint range of motion, facilitating hospital dismissal and preventing readmission. Traditionally, postoperative analgesia following major upper extremity surgery was provided by intravenous patient-controlled analgesia (PCA). However, opioids do not consistently provide adequate pain relief and often cause sedation, constipation, nausea/vomiting, and pruritus. Recently, clinical series have consistently reported that continuous brachial plexus block provided a superior quality of analgesia and surgical outcomes compared with systemic opioids but with fewer side effects. 4, 11 These reports suggest that continuous peripheral techniques may be the optimal analgesic method following elbow surgery. Appreciation of the indications, benefits, and side effects associated with both conventional and novel analgesic approaches is paramount to maximizing rehabilitative efforts and improving patient satisfaction.

MULTIMODAL ANALGESIA AND PERIPHERAL BLOCKADE
Multimodal analgesia is a multidisciplinary approach to pain management, with the aim of maximizing the positive aspects of the treatment while limiting the associated side effects. Because many of the negative side effects of analgesic therapy are opioid related (and dose dependent), limiting perioperative opioid use is a major principle of multimodal analgesia. Not surprisingly, the efficacy and side effects of analgesic therapy are major determinants of patient satisfaction. In a prospective survey of 10,811 patients, after adjusting for patient and surgical factors, moderate or severe post-operative pain and severe nausea and vomiting were associated with patient dissatisfaction. 18 The use of single-injection and continuous brachial plexus techniques and a combination of opioid and nonopioid analgesic agents for breakthrough pain results in superior pain control, attenuation of the stress response, and decreases opioid requirements.

CONVENTIONAL ANALGESIC METHODS

Parenteral Opioid Analgesics
When adequate analgesia is achieved with systemic opioids, side effects, including sedation, nausea, and pruritus, are common. However, despite these well-defined side effects, opioid analgesics remain widely used for postoperative pain relief. Systemic opioids may be administered by intravenous, intramuscular, and oral routes. Current analgesic regimens typically employ intravenous PCA for 24 to 48 hours postoperatively, with subsequent conversion to oral agents. The PCA device may be programmed for several variables including bolus dose, lockout interval, and background infusion. The optimal bolus dose is determined by the relative potency of the opioid; insufficient dosing results in inadequate analgesia, whereas excessive dosing increases the potential for side effects, including respiratory depression. Likewise, the lockout interval is based on the onset of analgesic effects; too short of a lockout interval allows the patient to self-administer additional medication before achieving the full analgesic effect (and may result in accumulation/overdose of the opioid). A prolonged lockout interval will not allow adequate analgesia. The optimal bolus dose and lockout interval are not known, but ranges have been determined ( Table 8-2 ). Varying the settings within these ranges appears to have little effect on analgesia or side effects. Although most PCA devices allow the addition of a background infusion, routine use in adult opioid-naïve patients is not recommended. There may be a role for a background opioid infusion in opioid-tolerant patients, however. Owing to the variation in patient pain tolerance, PCA dosing regimens may need to be adjusted in order to maximize the benefits and minimize the incidence of side effects. Despite the ease of administration and titratability, parenteral opioids may not provide adequate analgesia for major upper extremity surgery, particularly with movement, as evidenced by pain scores in the moderate to severe range in the first 2 days postoperatively. 16

TABLE 8-2 Intravenous Opioids for Patient-Controlled Analgesia
The adverse effects of opioid administration can cause serious complications in patients undergoing major orthopedic procedures. In a systematic review, Wheeler et al 25 reported gastrointestinal side effects (nausea, vomiting, ileus) in 37%, cognitive effects (somnolence and dizziness) in 34%, pruritus in 15%, urinary retention in 16%, and respiratory depression in 2% of patients receiving PCA opioid analgesia.

Nonopioid Analgesics
The addition of nonopioid analgesics reduces opioid use, improves analgesia, and decreases opioid-related side effects ( Table 8-3 ). The multimodal effect is maximized through selection of analgesics that have complementary sites of action. For example, acetaminophen acts predominantly centrally, whereas other nonsteroidal anti-inflammatory drugs (NSAIDs) exert their effects peripherally.

TABLE 8-3 Oral Nonopioid Analgesics

Acetaminophen
The mechanism of analgesic action of acetaminophen has not been fully determined. Acetaminophen may act predominantly by inhibiting prostaglandin synthesis in the central nervous system. Acetaminophen has very few adverse side effects and is an important addition to the multimodal postoperative pain regimen, although the total daily dose must be limited to less than 4000 mg. The administration should be scheduled (not just on an as-needed basis) to maximize the pharmacologic effects. It is also important to note that many oral analgesics are an opioid-acetaminophen combination ( Table 8-4 ). In these preparations, the total dose of opioid will be restricted to the acetaminophen ingested.

TABLE 8-4 Oral Opioid Analgesics

Nonsteroidal Anti-inflammatory Drugs
The NSAIDs have a mechanism of action through the cyclooxygenase (COX) enzymatic pathway, and ultimately block two individual prostaglandin pathways. The COX-1 pathway is involved in prostaglandin E 2 –mediated gastric mucosal protection and thromboxane effects on coagulation. The inducible COX-2 pathway is mainly involved in the generation of prostaglandins included in the modulation of pain and fever but has no effect on platelet function or the coagulation system. In general, NSAIDs block both the COX-1 and COX-2 pathways. Advantages of the COX-2 inhibitors are the lack of platelet inhibition and a decreased incidence of gastrointestinal effects.
The introduction of selective COX-2 inhibitors represented a breakthrough in perioperative pain management. Because they do not interfere with the coagulation system COX-2 inhibitors may be continued until the time of surgery and also may be administered in the immediate postoperative period. The perioperative administration of rofecoxib has been shown to have a significant opioid-sparing effect after major orthopedic surgery with no significant increase in perioperative bleeding. 22, 23 However, despite their efficacy, two (rofecoxib [Vioxx, Merck & Co., Whitehouse Station, NJ], valdecoxib [Bextra, Searle, Skokie, IL]) of three COX-2 inhibitors were voluntarily removed from general use because of an increased relative risk for confirmed cardiovascular events, such as heart attack and stroke, after 18 months of treatment.
The major side effects limiting NSAID use for postoperative pain control (renal failure, platelet dysfunction, and gastric ulcers or bleeding) are related to the nonspecific inhibition of the COX-1 enzyme. 24 Advantages of the COX-2 inhibitors are the lack of platelet inhibition and a decreased incidence of gastrointestinal effects. All NSAIDs have the potential to cause serious renal impairment. Inhibition of the COX enzyme may have only minor effects in the healthy kidney, but unfortunately can lead to serious side effects in elderly patients or those with a low-volume condition (blood loss, dehydration, cirrhosis, or heart failure). Therefore, NSAIDs should be used cautiously in patients with underlying renal dysfunction, specifically in the setting of volume depletion due to blood loss. 24 The effect of NSAIDs on bone formation and healing is of concern in the orthopedic patient population. Although the data are conflicting, there is evidence from animal studies that COX-2 inhibitors may inhibit bone healing. 7 Thus, the adverse effects of COX-2 inhibitors must be weighed against the benefits. Until definitive human trials are performed, it is reasonable to be cautious with the use of NSAIDs and COX-2 inhibitors, especially when bone healing is critical. To date, however, there is no evidence that COX-2 inhibitors have a clinically important effect on bone ingrowth.

Tramadol
Tramadol (Ultram, Ortho McNeil Pharmaceutical, Raritaran, NJ) is a centrally acting analgesic that is structurally related to morphine and codeine. Its analgesic effect is through binding to the opioid receptors as well as blocking the reuptake of both norepinephrine and serotonin. Tramadol has gained popularity because of the low incidence of adverse effects, specifically respiratory depression, constipation, and abuse potential. Tramadol has been shown to provide adequate analgesia, superior to placebo and comparable with various opioid and nonopioid analgesics for the treatment of acute pain. Thus, tramadol may be used as an alternative to opioids in a multimodal approach to postoperative pain, specifically in patients who are intolerant to opioid analgesics.

Oral Opioids
Oral opioids (see Table 8-4 ) are available in immediate-release and controlled-release formulations. Although immediate-release oral opioids are effective in relieving moderate to severe pain, they must be administered as often as every 4 hours. When these medications are prescribed “as needed” (prn), there may be a delay in the administration and a subsequent increase in pain. Furthermore, interruption of the dosing schedule, particularly during the night, may lead to an increase in the patient’s pain. The Acute Pain Management Guidelines developed by the Agency for Healthcare Policy and Research 1 recommend a fixed dosing schedule for all patients requiring opioid medications for more than 48 hours postoperatively. The adverse effects of oral opioid administration are considerably less compared with that of intravenous administration, and are mainly gastrointestinal in nature. 25
A controlled-release formulation of oxycodone (OxyContin, Purdue Pharma, Norwalk, CT) is also available and has been shown to provide therapeutic opioid concentrations and sustained pain relief over an extended time period. Administration of controlled-release oxycodone for 72 hours postoperatively improves analgesia and is associated with less sedation, vomiting, and sleep disturbances when compared with oxycodone given on either a fixed-dose or an as-needed basis. 21 Therefore, a multimodal analgesic approach may include scheduled administration of controlled-release oxycodone combined with prn oxycodone for breakthrough pain to maximize the analgesic effect and decrease the associated side effects.

CONTINUOUS BRACHIAL PLEXUS ANALGESIA
As previously discussed, although single-injection brachial plexus techniques have been used, the duration of effect is often not sufficient to result in substantial improvements in analgesia or outcome. 15 Recent applications of peripheral nerve block techniques have allowed prolonged postoperative analgesia (with an indwelling catheter) to assist rehabilitation and facilitate hospital dismissal. 3, 20 In addition, moderately severe upper extremity procedures, including total elbow arthroplasty, may be performed on an outpatient basis when analgesia is provided with an indwelling brachial plexus catheter. 11, 13 In all applications, the addition of a continuous brachial plexus catheter results in superior analgesia with fewer side effects than conventional systemic analgesic therapy. 4, 11
Brachial plexus catheters may be inserted using supraclavicular, infraclavicular, and axillary approaches. Although analgesia is produced in all nerve distributions, the block may not provide satisfactory surgical anesthesia, even with administration of more potent local anesthetic solutions. Therefore, continuous brachial plexus block is more often used to provide postoperative analgesia rather than intraoperative anesthesia. Catheters may be left indwelling for 4 to 7 days without adverse effects. 10 A continuous infusion of local anesthetic solution, such as bupivacaine 0.125%, prevents vasospasm and increases circulation after limb/digit replantation or vascular repair. More concentrated solutions (0.2% ropivacaine or bupivacaine) result in complete sensory block and allow early joint mobilization after painful surgical procedures to the elbow. 20 Local anesthetic selection is based on the duration and degree of sensory or motor block desired. 3, 12, 20 Because analgesic requirements vary with activity, a basal infusion with intermittent on-demand boluses allows greater flexibility. 12 The presence of dense sensory or motor block is not a contraindication to hospital dismissal. However, the patient should be informed of the anticipated duration of analgesia during the preoperative visit and instructed to protect the blocked extremity until block resolution ( Box 8-1 ).

BOX 8-1 Instructions for At-Home Brachial Plexus Catheter Patients

1. You are receiving local anesthetic through a small catheter near your nerves to help with your pain after surgery. This may not take away all of your pain but should help greatly. You may take your pain medicines as prescribed by your doctor. The nurse will review this with you. The local anesthetic will initially make your arm very numb. Over time, this degree of numbness will decrease, but usually your arm is not normal until the catheter is removed. Because your arm or leg will not function normally, YOU SHOULD NOT DRIVE.
2. The doctors and nurses will review the pump instructions with you. If you have any problems with the pump, call the technical support number or the number the doctor has given you.
3. Complications that could potentially occur include the following:
• The catheter may fall out. If this occurs, make sure to take some of your pain medicine and turn the pump off.
• Fluid may leak around the catheter. You can change or reinforce the dressing, if necessary. This is usually not a problem.
• The catheter may migrate into a blood vessel and cause high levels of local anesthetic. Symptoms of high levels of local anesthetic may include the following:
• Drowsiness
• Dizziness
• Blurred vision
• Slurred speech
• Poor balance
• Tingling around lips/mouth
• Other
4. You should keep your arm in a sling unless doing therapy.
5. Call your physician for medical assistance if any of the following symptoms occur:
• Unusual drowsiness
• Uncontrollable pain
• Uncontrollable vomiting
Neurologic dysfunction and intravascular injection are the primary concerns associated with peripheral blockade. However, in a large series involving more than 50,000 peripheral blocks, there were six seizures and 12 patients who reported postoperative nerve injury. Most neurologic complications were transient. 2 A series of nearly 4000 peripheral blocks, including 1650 axillary blocks, 69 patients (1.7%) developed transient neurologic dysfunction. 5 Complete recovery occurred in 4 to 12 weeks in all patients but one, who required 25 weeks. Despite the placement of a continuous catheter and extended exposure to local anesthetics, neurologic complications following indwelling brachial plexus catheters are uncommon, with the frequency similar to that of single-injection techniques. 3 Finally, the performance of a regional technique in a patient with a pre-existing neurologic condition remains controversial. Although the data are sparse, several retrospective series suggestthat these patients are not at a significantly increased risk of neurologic complications. 8, 9

INTRA-ARTICULAR CATHETERS
Intra-articular injection of local anesthetics is a well-established method of providing short-term analgesia in patients undergoing ambulatory procedures. Often near-complete pain relief is achieved for 4 to 6 hours, at which time the local anesthetic effect resolves and systemic analgesics are required. Recently, the introduction of disposable elastomeric and programmable pumps ( Fig. 8-3 ) has allowed extended infusion (2 to 4 days) of local anesthetic. 10 Because an intra-articular infusion does not provide complete blockade of the brachial plexus (compared with a neural sheath catheter), analgesia is often incomplete and oral opioids are required, although consumption is reduced. Note that all patients with infusions of local anesthetic solutions must be educated as to the signs and symptoms of local anesthetic toxicity and given instruction on how and when to call their physician for assistance (see Box 8-1 ).

FIGURE 8-3 Disposable pumps for intra-articular and neural sheath infusion at home. Portable infusion pumps (1) Accufuser (McKinley Medical, Wheat Ridge, CO); (2) Sgarlato (Sgarlato Labs, Los Gatos, CA), (3) Stryker PainPump, (Stryker Instruments, Kalamazoo, MI); (4) MedFlo II, (MPS Acacia, Brea, CA); (5), C-Bloc (I-Flow Corp, Lake Forest, CO); and (6) Microject PCA (Sorenson Medical, West Jordan, UT).
(From Ilfeld, B. M., Morey, T. E., and Enneking, F. K.: The delivery rate accuracy of portable infusion pumps used for continuous regional analgesia. Anesth. Analg. 95:1331, 2002.)
In summary, sustained and substantial outcome improvements, including joint range of motion and decreased hospital stay are dependent on the method or methods used to provide postoperative analgesia in patients undergoing surgery about the elbow. Recent studies have demonstrated that brachial plexus blocks combined with oral analgesics administered on a schedule provide a quality of analgesia and functional outcomes superior to systemic intravenous opioid analgesia and with fewer side effects. Continued collaborations between orthopedic surgeons and anesthesiologists are necessary to further advance the perioperative management of this patient population.

References

1 Acute Pain Management Guideline Panel. Acute pain management: operative or medical procedures and trauma-clinical practice guideline. AHCPR Pub No 92-0032. Rockville, MD: Agency for Health Care Policy and Research, Public Health Service, U.S. Department of Health and Human Services, 1992, p. 15.
2 Auroy Y., Benhamou D., Bargues L., Ecoffey C., Falissard B., Mercier F.J., Bouaziz H., Samii K. Major complications of regional anesthesia in France: the SOS regional anesthesia hotline service. Anesthesiology . 2002;97:1274.
3 Bergman B.D., Hebl J.R., Kent J., Horlocker T.T. Neurologic complications of 405 continuous axillary catheters. Anesth. Analg. . 2003;96:247.
4 Brown A.R. Anaesthesia for procedures of the hand and elbow. Best Pract. Res. Clin. Anaesthesiol. . 2002;16:227.
5 Fanelli G., Casati A., Garancini P., Torri G. Nerve stimulator and multiple injection technique for upper and lower limb blockade: Failure rate, patient acceptance, and neurologic complications. Study Group on Regional Anesthesia. Anesth. Analg. . 1999;88:847.
6 Fuzier R., Fuzier V., Albert N., Decramer I., Samii K., Olivier M. The infraclavicular block is a useful technique for emergency upper extremity analgesia. Can. J. Anaesth. . 2004;51:191.
7 Gajraj N.M. Cyclooxygenase-2 inhibitors. Anesth. Analg. . 2003;96:1720.
8 Hebl J.R., Horlocker T.T., Sorenson E.J., Schroeder D.R. Regional anesthesia does not increase the risk of postoperative neuropathy in patients undergoing ulnar nerve transposition. Anesth. Analg. . 2001;93:1606.
9 Hebl J.R., Kopp S.L., Schroeder D.R., Horlocker T.T. Neurologic complications after neuraxial anesthesia or analgesia in patients with preexisting peripheral sensorimotor neuropathy or diabetic polyneuropathy. Anesth. Analg. . 2006;103:1294.
10 Ilfeld B.M., Enneking F.K. A portable mechanical pump providing over four days of patient-controlled analgesia by perineural infusion at home. Reg. Anesth. Pain Med. . 2002;27:100.
11 Ilfeld B.M., Morey T.E., Enneking F.K. Continuous infraclavicular brachial plexus block for postoperative pain control at home: a randomized, double-blinded, placebo-controlled study. Anesthesiology . 2002;96:1297.
12 Ilfeld B.M., Morey T.E., Enneking F.K. Infraclavicular perineural local anesthetic infusion: a comparison of three dosing regimens for postoperative analgesia. Anesthesiology . 2004;100:395.
13 Ilfeld B.M., Wright T.W., Enneking F.K., Vandenborne K. Total elbow arthroplasty as an outpatient procedure using a continuous infraclavicular nerve block at home: A prospective case report. Reg. Anesth. Pain Med. . 2006;31:172.
14 Koscielniak-Nielsen Z.J., Rotboll N.P., Risby M.C. A comparison of coracoid and axillary approaches to the brachial plexus. Acta Anaesthesiol. Scand. . 2000;44:274.
15 McCartney C.J., Brull R., Chan V.W., Katz J., Abbas S., Graham B., Nova H., Rawson R., Anastakis D.J., von Schroeder H. Early but no long-term benefit of regional compared with general anesthesia for ambulatory hand surgery. Anesthesiology . 2004;101:461.
16 McGrath B., Elgendy H., Chung F., Kamming D., Curti B., King S. Thirty percent of patients have moderate to severe pain 24 hr after ambulatory surgery: a survey of 5,703 patients. Can. J. Anaesth. . 2004;51:886.
17 Morrey B.F., Bryan R.S. Complications of total elbow arthroplasty. Clin. Orthop. . 1982;170:204.
18 Myles P.S., Williams D.L., Hendrata M., Anderson H., Weeks A.M. Patient satisfaction after anaesthesia and surgery: results of a prospective survey of 10,811 patients. Br. J. Anaesth. . 2000;84:6.
19 Neal J.M., Hebl J.R., Gerancher J.C., Hogan Q.H. Brachial plexus anesthesia: essentials of our current understanding. Reg. Anesth. Pain Med. . 2002;27:402.
20 ODriscoll S.W., Giori N.J. Continuous passive motion (CPM): theory and principles of clinical application. J. Rehabil. Res. Dev. . 2000;37:179.
21 Reuben S.S., Connelly N.R., Maciolek H. Postoperative analgesia with controlled-release oxycodone for outpatient anterior cruciate ligament surgery. Anesth. Analg. . 1999;88:1286.
22 Reuben S.S., Connelly N.R. Postoperative analgesic effects of celecoxib or rofecoxib after spinal fusion surgery. Anesth. Analg. . 2000;91:1221.
23 Reuben S.S., Fingeroth R., Krushell R., Maciolek H. Evaluation of the safety and efficacy of the perioperative administration of rofecoxib for total knee arthroplasty. J. Arthroplasty . 2002;17:26.
24 Stephens J.M., Pashos C.L., Haider S., Wong J.M. Making progress in the management of postoperative pain: a review of the cyclooxygenase 2-specific inhibitors. Pharmacotherapy . 2004;24:1714.
25 Wheeler M., Oderda G.M., Ashburn M.A., Lipman A.G. Adverse events associated with postoperative opioid analgesia: a systematic review. J. Pain . 2002;3:159.
CHAPTER 9 Principles of Elbow Rehabilitation

Jay Smith, Bernard F. Morrey

INTRODUCTION
The goal of elbow rehabilitation is to restore optimal, pain-free function within the anatomic and physiologic limitations of the patient. To achieve this goal, the clinician should adhere to several principles to guide the rehabilitation process: (1) establish a complete and accurate diagnosis, (2) control pain and inflammation, (3) implement early, atraumatic motion, (4) re-establish neuromuscular control about the elbow, and (5) rehabilitate the elbow in context of the kinetic chain. The purpose of this chapter is to review these principles as they apply to a wide variety of atraumatic and atraumatic elbow disorders. For more detailed discussion of specific rehabilitation protocols, readers are referred to the appropriate chapters in this text.

ESTABLISH A COMPLETE AND ACCURATE DIAGNOSIS
Successful rehabilitation is predicated on a complete understanding of the anatomic and physiologic factors pertaining to a particular elbow disorder. The elbow joints (humeroulnar, humeroradial, proximal radioulnar), nerves, vessels, capsule and ligaments, and muscles, as well as adjacent articulations (distal radioulnar and shoulder) should be considered. Anatomic alterations in these tissues will define initial motion restrictions as well as the potential for restoration of motion and stability. However, it is ultimately the patient’s physiologic age and biologic healing potential that will determine how much of this potential is realized. Some patients heal poorly and may be prone to ongoing instability, whereas others exhibit a propensity for scar formation and will develop stiffness despite the best efforts of the treatment team. 32 From our perspective, this sometimes dramatic individual variation in the healing response assumes a dominant role in the recovery of some patients.
Throughout the rehabilitation process, the physiologic stage of healing directly affects the rehabilitation program. 50 During the inflammatory stage, the primary goals are pain and edema control and adherence to stable arcs of motion to protect tissues at risk. During the fibroblastic phase, controlled stresses may be increased to promote more normal collagen formation, and low-level strengthening is implemented to re-establish neuromuscular control. Finally, during the remodeling phase, stretching and strengthening exercises are advanced, and functional restoration is pursued. The clinician must be constantly aware of the physiologic status of the elbow. The elbow is an unforgiving articulation with significant bony congruity and a tendency to develop inflammation and stiffness. 32 Overzealous rehabilitation efforts can quickly regress the elbow from the fibroblastic phase back into the inflammatory phase. Consequently, clinicians should constantly monitor the status of the elbow and modify the rehabilitation program accordingly. This process requires appropriate follow-up, patient education, and constant communication between members of the treatment team.

PATIENT PARTICIPATION
As with any successful program, but particularly at the elbow, the patient must be made to understand their role in the recovery process. The clinician and therapist must avoid having the patient become dependent on them, or on formal rehabilitation sessions. The key is to successfully transfer responsibility for improvements to the patient. They become their own therapists.

REDUCE PAIN AND INFLAMMATION
During the acute post-traumatic or postsurgical period, the primary goal is to control pain and inflammation. The elbow tends to get stiff as a result of adhesion formation and muscular cocontraction. 32, 50 PRRICEMM principles are applied to reduce pain, edema, and inflammation— P rotection, relative R est, I ce, C ompression, E levation, M edications, and M odalities.



Protection and Relative Rest
Appropriate protection and relative rest require balancing the need to protect healing tissues with the adverse effects of immobility. Total immobility can precipitate rapid deconditioning, whereas tenuous tissues can be easily damaged by aggressive motion. 2, 4, 21, 50 Diagnosis-specific safe elbow motion arcs guide early motion and are discussed in the next section. Bracing or splinting is often prescribed to protect healing tissues and are discussed in Chapter 11 . Patients can immediately initiate general aerobic fitness programs (e.g., Exercycle) and exercises with their three unaffected limbs. With respect to the affected limb, patients may perform wrist-hand and shoulder motions while avoiding injurious elbow positions or loads. For example, shoulder abduction will produce a varus elbow stress and therefore is contra-indicated in the early post-traumatic/post-operative period after lateral collateral ligament complex injury/reconstruction. 41

Ice
Physiologically, ice can reduce inflammation, modulate pain and control muscle spasm. 10 Ice is applied regularly in the acute post-traumatic/postoperative period, and intermittently postexercise/postactivity in the later phases of healing. 50 Caution should be exercised when applying ice over traversing nerves, particularly those that have been surgically transposed. 7

Compression and Elevation
Compression wrapping and elevation above heart level promote edema control. Both static and intermittent air-compression devices have been successfully used in the early stages of rehabilitation. Although published scientific investigation is lacking, a case-control pilot study from our institution documented a statistically significant advantage with respect to edema control for a compression cryotherapy device (Aircast) applied following total elbow arthroplasty ( Fig. 9-1 ). 1

FIGURE 9-1 Cryocuff (Aircast) provides both compression and cold to the elbow.

Medications
Medication use is determined by the specific diagnosis, healing stage, and physician preference. Narcotics, nonsteroidal anti-inflammatory drugs (NSAIDs), and acetaminophen are used based upon an individualized risk-benefit ratio analysis. Although NSAIDs may provide short-term analgesic benefits in lateral elbow tendinopathy (“tennis elbow”), 20 they are typically used with more caution in the post-traumatic/postsurgical elbow. Some NSAIDs inhibit platelets and may result in hemorrhage, whereas others may actually inhibit the healing response. 30, 48 Nonetheless, controlling inflammation with medication is an important element of the postinjury/postoperative recovery period.
Patients with inflammatory arthropathies may benefit from rheumatologic consultation to optimize systemic medications. In tennis elbow, corticosteroid injections do provide reliable relief for 4 to 6 weeks in most cases but may not affect long-term outcome and often cause temporary symptom exacerbation. 27, 45 Further investigation is needed to clarify the initial positive results reported for topical nitric oxide, 42 platelet-rich plasma injections, 31 and botulinum toxin injections 24 in tennis elbow. Interested readers are referred to Chapter 44 for a more in depth discussion.

Modalities
Other than ice, the role of modalities in the acute post-traumatic/postsurgical period remains poorly defined. During periods of muscle inhibition, high-voltage galvanic stimulation (HVGS)–induced muscle contractions have been used to reduce pain and edema. 50 As elbow motion improves, electromyographic (EMG)-biofeedback can be used to reduce muscle co-contractions, initially inhibiting the antagonists and subsequently cuing on the agonists. 13, 50 These modalities should be applied carefully in conjunction with constant reassessment.
With respect to tennis elbow, iontophoresis appears to offer some short-term benefit, 38 the roles of acupuncture and shock wave therapy remain inconclusive, 8, 11 and pulsed electrical magnetic stimulation 47 and laser therapy 8 appear to have no role.

IMPLEMENT EARLY ATRAUMATIC MOTION
The elbow exhibits a marked tendency to rapidly develop intra-articular and periarticular adhesions, resulting in motion loss that may eventually compromise outcome. 32 Early motion is desirable to minimize or prevent adhesion formation, 32, 51 mitigate against the deleterious effects of immobility, 2, 4, 21, 50 facilitate lymphatic and venous drainage, 13 and modulate pain through proprioceptive mechanisms. 4, 13, 52 These benefits must be weighed against the risk of irritating healing tissues, thereby deleteriously affecting the rehabilitation program.
The long-term range-of-motion goals for the patient must be established, and the patient must have a clear understanding of this goal. The potential range of motion is defined by the specific diagnosis and any post-traumatic/postsurgical anatomic alterations. Whether this potential is achieved depends on the ability of the rehabilitation program to optimize the patient’s physiology, as well as the patient’s compliance with the program. Normal elbow range of motion is 0 to 5 degrees of hyperextension, 134 to 145 degrees of flexion, 75 degrees pronation, and 85 degrees supination. 28, 35 Most activities of daily living are performed within 30 to 130 degrees flexion, 50 degrees pronation, and 50 degrees supination. 28, 35 However, some daily activities (e.g., reaching to the opposite side of the head), as well as many recreational and vocational activities, may require greater motion. 17, 36 The patient and the treatment team must understand the expected limitations of the elbow in the context of the potential functional needs, thereby defining realistic functional expectations for “success.”
To implement early, atraumatic motion, the clinician must completely understand the patient’s anatomy and physiologic healing stage with respect to all tissues involved—joints, capsule, ligaments, muscle-tendon units, nerves, and vessels. In addition, the elbow must be constantly reassessed for increased pain, swelling, or motion loss, and the rehabilitation program modified accordingly. The initial arc of protected elbow motion is diagnosis specific. For example, a dislocated elbow with lateral ulnar collateral ligament (LUCL) insufficiency is most stable in flexion and pronation, 15, 33, 40 whereas a dislocation with bilateral ligament injuries (LUCL and medial ulnar collateral ligament [MUCL]) and a radial head fracture is kept in neutral pronation-supination to modulate humeroradial contact stress while balancing ligamentous tension. 13, 32 A normally located ulnar nerve may be irritated by excessive or prolonged flexion, whereas a transposed ulnar nerve, particularly if adhered, may be irritated by excessive or prolonged extension. 50 Interested readers are referred to Chapters 28 , 29 , and 48 for more diagnoses-specific in-depth discussion.
As previously discussed, elbow bracing or splinting may be protective in the postoperative/post-traumatic period by controlling position and forces, as well as providing external stability. 9 As healing progresses to the fibroblastic and remodeling phases, braces may be used to restore motion. 9 Appropriate prescription, application, and compliance are the keys to success. 9, 18, 26 Specific applications are discussed in Chapter 11 .

TIMING
Once safe motion arcs have been defined, motion can be prescribed based on the stage of tissue healing. 13, 50 A complete clinical examination is necessary to determine the healing stage, as well as the specific tissue or tissues responsible for the motion loss. 32 Assessing both the quality and quantity of motion loss is necessary to accurately prescribe range of motion within the restrictions. Bony motion blocks will not respond to rehabilitation efforts, and well-established soft tissue contractures with a hard end-feel will not respond as reliably as those with a springier end-feel. 50 During the inflammatory phase, range of motion must not be aggressive, and must strictly adhere to restrictions while monitoring for regression. As the elbow enters the fibroblastic and eventually remodeling phases, range of motion may become more aggressive because tissues have healed sufficiently to absorb additional forces that will be beneficial to promote collagen reformation. During these latter phases, the clinician must constantly monitor for signs of inflammation and modify the program accordingly. Four types of range of motion are typically used during elbow rehabilitation: active assisted, active, passive, and resisted.
Regardless of each type, the role of the therapist must never be so aggressive as to aggravate pain or incite inflammation.


Active Assisted Range of Motion
Active assisted range of motion (AAROM) is typically implemented earliest, including during the inflammatory phase. Goals are prevention of intra-articular and periarticular adhesions, promotion of cartilage healing, edema control, and pain modulation. 13 Maintaining low levels of voluntary muscle activation minimizes elbow joint compression and shear forces. Gravity-assisted motion is often used during this phase, as is continuous passive motion (CPM) (see Chapter 10 ). Although CPM is by definition “passive,” in the early post-traumatic/postoperative period, its benefits parallel those of AAROM.
During gravity-assisted flexion, the patient is positioned supine on the table, upper limb flexed to 90 degrees, and the elbow allowed to flex under the pull of gravity, as guided and assisted by the well arm. 13 Gravity-assisted extension may be performed sitting with the upper limb supported, and the elbow allowed to extend under the influence of gravity, assisted by the well arm. 13 Both exercises may be initiated during the inflammatory phase with diagnosis specific restrictions. As pain and edema subside, the amount of gravity and well arm assistance may be decreased, eventually transitioning to active range of motion.

Active Range of Motion (AROM)
Active range of motion (AROM) may initially be performed in gravity-eliminated positions (e.g., table top flexion-extension) before transitioning to antigravity positions (e.g., sagittal plane flexion-extension). Benefits of AROM parallel those of AAROM, with added benefit that AROM voluntarily activates the elbow muscles, thus stimulating neuromuscular control. AROM is performed within safe flexion-extension and pronation-supination motion arcs while monitoring loads placed on the elbow due to upper limb positioning (e.g., effect of forearm pronation on humeroradial compression force, 34 effect of shoulder abduction on elbow varus force). 41

Passive Range of Motion (PROM)
Passive range of motion (PROM) may be initiated as patients enter the fibroblastic phase, or during the remodeling phase. The goal of PROM, in the form of splinting or stretching, is to induce permanent tissue length changes to gain motion. 50 Clinical research supports the efficacy of appropriately applied progressive static splinting for elbow contractures 19 (see Chapter 11 ). Although no form of stretching has been proven superior in the elbow, low-load, long-duration (LLLD) stretches are commonly used based upon supportive basic science research 22 and clinical experience. 50 The LLLD stretch for the anterior elbow is performed with the patient’s elbow supported, forearm held in supination to optimize anterior capsule tension 19 and a small weight or low-resistance exercise band held in the hand 50 ( Fig. 9-2 ). Patients perform several repetitions of a 20-second to 2- to 3-minute stretch, or one or two repetitions of a 10- to 12-minute stretch. 22, 46, 50 In either case, stretches are followed by AROM to re-establish neuromuscular control within the newly obtained motion arcs. The process is completed by icing the affected area in a lengthened position to reduce inadvertent inflammation produced during the stretch and to allow cooling in a lengthened position. 46

FIGURE 9-2 Low-load long-duration stretch for anterior elbow soft tissue tightness. Elbow supported and forearm supinated to increase anterior capsular stretch. See text for details.
During the fibroblastic and remodeling phases, additional modalities may be beneficial to facilitate motion. Use of superficial heat in the form of hot packs, whirlpool, fluidotherapy, or a heating pad will increase local blood flow and tissue extensibility while decreasing stiffness and muscle spasm. 3, 49 Therefore, superficial heat may serve an adjunctive role to stretching and splinting, provided that no signs of inflammation are present. There exists a paucity of data investigating the role of ultrasound (US) in specific clinical conditions about the elbow. 8, 44 Limited data suggest that low-intensity, pulsed US may promote wound healing and increase fibroblastic activity while controlling inflammation, 39, 48 whereas high-intensity US may increase the extensibility of scar tissue through heating, particularly when accompanied or followed by stretching. 8, 39, 44, 46 There are insufficient data to support or refute the role of US in chronic tendinopathies, which can be considered a dysfunctional fibroblastic phase, although the majority of data suggest that phonophoresis (US with corticosteroid) does not offer any additional benefit over US alone. 8, 45

Resisted Range of Motion (RROM)
Resisted range of motion (RROM) is implemented as healing allows and after AROM has been established. Therefore, formal implementation of RROM, other than antigravity AROM, is typically delayed for 8 to 12 weeks. The primary goal of RROM is to restore neuromuscular control about the elbow, a principle discussed in the following section.

Joint Mobilization and Neural Gliding
This approach has been advocated as an adjunctive technique to increase motion during elbow rehabilitation. 12, 50 In theory, joint mobilizations may reduce pain, spasm, and stiffness, but supportive scientific data are lacking. 13, 50 In practice, therapists will initiate low-amplitude oscillatory motions and progress to higher amplitude distraction techniques as tissue healing allows. 13, 50 Joint mobilizations may be preceded by heat, and are followed by PROM/stretching to gain motion, and thereafter by AROM to control the newly gained motion, as noted above. Neural gliding consists of gentle exercises to promote nerve mobility with respect to surrounding tissues and has been promoted to disperse intraneural edema, optimize axonal transport, reduce nerve adhesions, and relieve nerve-related pain. 12 At this time, there is insufficient evidence to support or refute the practice of joint oscillations or neural glide techniques during the elbow rehabilitation process. Consequently, prescription should be based on the assessment of the risk-benefit ratio, availability of qualified practitioners, and financial and time constraints.

RESTORE REGIONAL NEUROMUSCULAR CONTROL
Consideration of the status of the joint is essential with this component of rehabilitation. If the joint cartilage is compromised or if the joint surface is compromised, this element of rehabilitation should be described primarily to accomplish activities of daily living.
If the joint allows, in order to optimize elbow function, neuromuscular control (NMC) must be re-established. NMC includes strength, endurance, and coordinated muscle contractions. NMC is a prerequisite to capitalize on the functional potential provided by the range-of-motion gains during the rehabilitation program. In addition, NMC about the elbow may provide some ability to compensate for persistent instabilities despite optimal treatment. For example, coordinated muscle contraction can dynamically improve elbow stiffness, 5 and at least partially compensate for instability after LUCL 15 and MUCL 14, 43 injury or reconstruction.
Early NMC training is achieved through the AAROM exercises, as previously discussed. Positions and motions are chosen based on diagnosis-specific restrictions and modified accordingly over time. As healing allows, RROM (i.e., strengthening) exercises are initiated. Strengthening exercises are prescribed in the context of a graduated program, initially emphasizing low-load, low-repetition exercise sessions performed multiple times per day (e.g., one to two sets of 10 to 20 repetitions three to five times/day). This scheme re-establishes motor control pathways while minimizing edema and overload risk. 50 Finger flexion-extension, wrist ulnar-radial deviation, forearm pronation-supination, and elbow flexion-extension are included. Initial isometric contractions can minimize atrophy and may provide some strength gains while controlling joint stress. Typically, 3- to 6-second submaximal isometric contractions are followed by 3 to 6 seconds of rest, repeated 10 to 20 times. Isometric exercises are initially completed in the most stable position for the patient, and are repeated two to three times per day. As the clinical situation allows, frequency is increased, less stable positions are included, and external resistance in the form of free weights, cables, or resistance tubing/bands is added. The optimal repetition-load scheme for strengthening about the elbow remains elusive, but frequency should be stressed over load, at least initially. 5, 13 It is not uncommon to start resisted elbow flexion exercises with a 1/4 or 1/2 kg weight, performing one set of 10 repetitions three to four times per day. As the rehabilitation progresses, loads and repetitions may be adjusted to meet the specific strength-endurance needs of the patient. Although eccentric-biased strengthening may have a role in chronic tennis elbow, 29 this strengthening mode has a limited role in general elbow rehabilitation.
As NMC is re-established, it is important to continually monitor the status of the elbow to ensure that injury or irritation is not occurring. In addition, the clinician must remain cognizant of safe versus unsafe positions and motion arcs, and modify the rehabilitation programaccordingly. For example, initially after MUCL reconstruction or injury, the elbow is inherently more stable with the forearm supinated. In this position, resisted finger flexion, wrist flexion ( Fig. 9-3A ) and ulnar deviation (see Fig. 9-3B ) exercises may be safely performed to strengthen the dynamic medial elbow stabilizers as long as valgus loads are avoided by appropriate positioning. 5, 14, 43 After LUCL injury or reconstruction, wrist extensor strengthening may be performed with the forearm pronated and supinator strengthening with the forearm supinated, in both cases to avoid a varus load on the elbow. 15 Following elbow dislocation, the elbow is initially exercised in flexion due to the consistent posterior force vectors of the elbow musculature. 33

FIGURE 9-3 A, Resisted wrist flexion exercise with forearm supinated to minimize elbow valgus stress after medial ulnar collateral ligament injury/repair. B, Similar to Figure 9-3A , with resisted ulnar deviation (targeting the flexor carpi ulnaris [FCU]) performed in midprosupination to minimize elbow valgus stress.

INTEGRATION INTO THE KINETIC-KINEMATIC CHAIN
Regardless of pathoetiology, the elbow should not be rehabilitated in isolation of other joints. The elbow represents an important part of the kinetic-kinematic chain, whereby forces and motions are generated, transformed, and transferred through multiple body segments to the hand for the purpose of function. 25 As a matter of fact, even if little is being done actively for the elbow, the other joints should be addressed during the recovery period. Throughout the rehabilitation process, patients are encouraged to exercise the entire body, including ipsilateral shoulder and wrist. Programs are tailored to each patient’s anticipated needs and generally include both resistance and aerobic exercise modes. As previously mentioned, the clinician should consider the position of the elbow, and consequent direct and indirect forces at all times during this process. As the elbow improves, integrated total body exercises are implemented and advanced with the goal of return to daily life, work, and sport.
Research continues to elucidate the affect of proximal kinetic-kinematic chain dysfunction on incurred elbow stress. 25 Consequently, clinicians should evaluate the kinetic-kinematic chain for deficits in flexibility, strength, and coordination that may be pathoetiologic in the presenting elbow disorder. A technique coach or occupational medicine specialist may identify and rectify technique flaws that produce inefficient movement and consequently overstress the elbow. 16, 23 In some cases, it may be necessary to intentionally increase motion or strength, or both, at adjacent body segments to compensate for permanent elbow deficits (e.g., increased shoulder abduction and internal rotation compensating for forearm pronation loss).
Finally, a qualified professional should evaluate the patient’s work or sporting environment and relevant equipment to identify modifiable risk factors that may have contributed to the presenting elbow disorder. 37 Placing the patient and the elbow back into the same situational stress may lead to symptom recurrence, and may compromise outcome and satisfaction.

SUMMARY
Elbow rehabilitation is a challenging and dynamic process. The commitment of the physician, therapists, and patient and understanding their subjective roles is essential for success. A complete understanding of elbow mechanics and pathomechanics, open communication between patients and all members of the rehabilitation team, and patience is essential. By following the general principles outlined in this chapter ( Box 9-1 ), cliniciansmay successfully rehabilitate a wide variety of elbow disorders while minimizing complications.

BOX 9-1 Principles of Elbow Rehabilitation

1. Establish a Complete and Accurate Diagnosis
a. Consider all tissues involved
b. Understand anatomic alterations
c. Assess physiologic healing stage
d. Reassess throughout rehabilitation
e. Communication—patient, surgeon, rehabilitation team
2. Control Pain and Inflammation
a. PRRICEMM principles
3. Implement Early Atraumatic Motion
a. AAROM → AROM → AAROM + PROM → RROM
b. CPM (see Chapter 10 )
c. Monitor elbow for regression
4. Restore Regional Neuromuscular Control
a. Frequency >> Intensity
b. Isometric exercises initially
c. Control elbow position and loads
5. Integration into the Kinetic-Kinematic Chain
a. Elbow rehabilitation = total body rehabilitation
b. Treat kinetic-kinematic chain deficits
c. Evaluate equipment, training, and movement skills

References

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CHAPTER 10 Continuous Passive Motion

Shawn W. O’Driscoll

INTRODUCTION
In 1960, Salter and Field 16 showed that immobilization of a rabbit knee joint under continuous compression, provided by either a compression device or forced position, resulted in pressure necrosis of cartilage. In 1965, Salter and colleagues 17 reported the deleterious effects of immobilization on the articular cartilage of rabbit knee joints and the resultant lesion that they termed obliterative degeneration of articular cartilage. Salter 15 believed that, “The relative place of rest and of motion is considerably less controversial on the basis of experimental investigation than on the basis of clinical empiricism.” He reasoned that because immobilization is obviously unhealthy for joints, and if intermittent movement is healthier for both normal and injured joints, then perhaps continuous motion would be even better. Because of the fatigability of skeletal muscle, and because a patient could not be expected to move his or her own joint constantly, he concluded that for motion to be continuous, it would also have to be passive. Thus, he invented the concept of continuous passive motion , which has come to be known as simply CPM. Salter also believed that CPM would have an added advantage; namely, that if the movement was reasonably slow, it should be possible to apply it immediately after injury or operation without causing the patient undue pain.

FOUR STAGES OF ELBOW STIFFNESS
Because the elbow is so prone to post-traumatic and postsurgical stiffness, CPM should be especially useful in maintaining motion and preventing such stiffness. The rationale for this is much clearer if one understands the stages of stiffness, of which there are four.
The first stage, occurring within minutes to hours following surgery or trauma, is caused by bleeding. The second stage, which occurs during the next few hours and days is very similar but progresses more slowly. It is due to edema . Both bleeding and edema result in swelling of the periarticular tissues, thereby diminishing their compliance. The immediate effect is to limit joint motion and make it more painful and, therefore, less acceptable to the patient. Thus, stiffness in these first two stages is avoided by preventing swelling. This can be accomplished by ensuring that the joint is moved through its entire range of motion right from the start, rather than only a portion of its range. CPM is required for this purpose.
The third stage is characterized by deposition of extracellular matrix and the formation of granulation tissue commencing near the end of the first week. It continues for days or weeks. The stiffness is still soft but may require the use of splints to regain motion. The fourth stage commencing after about a month results from fibrosis and is often amenable only to splinting or surgical treatment.

PRINCIPLES OF USE
Based on an understanding of how stiffness develops, the principles of use of CPM are readily understandable. Until motion is started, it is preferable to elevate the limb with the elbow in full extension and wrapped in a Jones dressing to minimize swelling. It should not be a compressive wrap because of the risk of losing circulation. A drain is usually useful to prevent accumulation of blood. Before starting CPM, all circumferential wrapping (e.g., Jones, cling) should be removed and replaced with a single elastic sleeve. Failure to do this may cause soft tissue injuries due to shear stresses.
Once CPM is started, it is optimal that the full potential range of motion of that specific joint be used ( Fig. 10-1A and B ). Essentially, the tissues are being squeezed alternately in flexion and extension. CPM causes a sinusoidal oscillation in hydraulic pressure within and around the joint. 2, 9 This not only rids them of excess blood and fluid but prevents further edema from accumulating. 8 In the first 24 hours, swelling can develop in minutes (due to bleeding), so CPM should be virtually continuous. This has a beneficial effect on healing soft tissues similar to that seen with compressive therapy after eccentric muscle injury. 6 Bathroom privileges are allowed, and the patient is instructed to come out of the CPM device once every hour for 5 minutes. This safety precaution is to reduce the risk of a pressure or stretch related nerve palsy. As the number of days following surgery increases, the amount of time required for swelling to develop increases also, so that longer periods out of the machine are permitted.

FIGURE 10-1 A to C, The range of motion on continuous passive motion should be full. This permits the tissues to be squeezed alternately in flexion and extension. Analgesia is accomplished with an indwelling catheter for continuous brachial plexus block anesthesia using bupivacaine, a long-acting local anesthetic.
CPM requires close supervision by someone skilled with its use, so it is mandatory that the patient and family are involved and educated from the beginning regarding the principles of use and how to monitor the limb. Frequent checking and slight adjustments of position prevent pressure-related problems. The arm tends to slip out of the machine, so it must frequently be pulled back into it. Nurses do not always have sufficient time, or sometimes the experience, to look after these needs. The patients and their families develop a keen sense of responsibility very quickly and become an invaluable asset. A preoperative instructional video is useful to educate them and should be watched again postoperatively.
The CPM should be used long enough to get the patient through the period during which he or she will be unable to accomplish the full range of motion by himself or herself. This can be several days to a month. For most contracture releases, it tends to be used for four weeks.

PAIN CONTROL
Such use of CPM immediately raises questions and concerns regarding uncontrollable pain. Pain control in these patients requires that we depart from traditional teaching. Rather than adjusting the motion according to the level of pain, the analgesia is adjusted instead. This is no different from the principles of anesthesia for surgery. Some patients have more pain than others, and appropriate modifications need to be made for them.
We favor the use of an indwelling catheter for continuous brachial plexus block anesthesia (see Fig. 10-1C ). 13 - 17 This permits a range from analgesia to anesthesia by varying the dose of bupivacaine, a long-acting local anesthetic. The initial bolus dose may be sufficient to cause a complete or near-complete motor and sensory block. Motor blockade requires splinting of the wrist to protect it. Moderate or complete anesthesia, as opposed to analgesia with minimal anesthesia, requires careful attention to the status of the limb overall, because the patient’s protective pain response is no longer present. Insidious development of a nerve palsy during CPM may be less likely to go unnoticed if some motor and sensory function are still present in each nerve during CPM.
The catheter is left in place for 3 days in hospital, then removed. At that time, the patient is usually able to maintain the same range of motion with either no or only oral analgesics. The goal is to have the patient leave the hospital capable of moving the elbow from about 10 to 140 degrees of motion actively. Of course, full motion is preferred.
A patient-controlled analgesia pump with mor-phine has also been used effectively if a brachial plexus block is contraindicated, unsuccessful, or not available.

ADVANTAGES
There are a number of advantages to the use of CPM. Most surgeons are aware from the total knee experience that analgesic consumption is diminished because the patients are more comfortable (although not always during the first day or two). Swelling is diminished.
Although most experience with CPM has been in the knees, several studies have documented the efficacy of CPM for the elbow. 1, 5, 11, 12 In two separate studies, postoperative CPM was found to improve elbow motion following open reduction internal fixation (ORIF) of distal humeral fractures in children and adolescents. 11, 12 CPM has been also documented to be effective in assisting with restoration of elbow motion after surgical release 1 or resection of heterotopic ossification. 5
My personal experience using CPM in strict accordance with the principles just outlined has convinced me that motion is obtained faster and more completely than that obtained without the use of CPM, despite the studies that failed to show such a benefit in the knee ( Fig. 10-2A and B ). 7, 8, 18, 19 This can be explained on the basis of how CPM has been routinely used. Typical protocols involve starting with a small range of motion tolerated by the patient, for example 30 degrees, and gradually increasing the range each day. This pattern of use is not in compliance with the essential principles of CPM. What such a protocol does is to increase swelling and bleeding due to constant tissue irritation.

FIGURE 10-2 Typical range of motion seen 3 weeks postoperatively ( A ) and 1 year postoperatively ( B ) following a distraction interposition arthroplasty treated postoperatively using continuous passive motion.
The most astonishing benefit of CPM, however, is how rapidly the patient is capable of pain-free and relatively full function and, therefore, return to work and sport.

COMPLICATIONS
In using CPM for the elbow, I have become aware of the protocol for complications. Bleeding is increased but rarely sufficiently to require a transfusion, although some patients have been taken back to the operating room for evacuation of a hematoma under such circumstances. Those elbows were treated by being placed back into a well-padded Jones dressing with an anterior plaster slab holding the elbow in extension, then elevating the arm for 2 to 4 days. It is clear to me that in certain settings, CPM can increase the risk of soft tissue and wound healing complications. Hematomas and seromas, as just mentioned, are more likely if CPM is used after having raised a skin flap as part of the exposure. When large skin flaps have been raised and the extent of deep dissection has been extensive, CPM may cause shearing of the soft tissues that is not able to be tolerated. This leads to dark discoloration of the skin, possibly full thickness necrosis, blistering and/or persistent weeping through the wound. If the wound is not closed very securely (subcuticular stitches are insufficient), it may dehisce. I have changed my use of skin incisions and CPM in these types of cases for these reasons. In such circumstances I prefer medial/lateral incisions with no skin flaps rather than a posterior incision. If I am concerned about soft tissues, I delay the use of CPM for 2 to 4 days until I see how the tissues respond to the surgery itself. Despite these concerns, no patients have lost a flap, although a few have had areas of necrosis that healed by secondary intention without further surgery. One patient almost fell out of bed from lying so close to the edge while using the machine.
A word of caution is required. No circumferential wrapping (e.g., cling) should be left on the elbow once the CPM is started. A single elastic tube grip sleeve is best.
I do not generally use CPM in the presence of ligament injuries or potential joint instability because it is not possible to keep the elbow perfectly aligned with the axis of rotation of the machine. Malalignment would stress the ligaments and bony stabilizers of the joint.
Neurologic complications of CPM are well recognized for the leg. With the elbow, CPM can permit pressure-induced palsies, which can be prevented as discussed earlier. Delayed-onset ulnar neuropathy is a risk after contracture release. It appears to be due to compression by the cubital tunnel retinaculum and can largely be prevented by prophylactic nerve decompression. Obviously, any nerve can develop a palsy from stretch as well.

INDICATIONS AND CONTRAINDICATIONS
CPM is indicated to prevent stiffness and to retain motion obtained at the time of surgery, particularly following contracture release, synovectomy, and excision of heterotopic ossification. I do not generally use it following the replacement of arthritic joints that were stiff preoperatively because of concern about soft tissue complications that would be serious overlying a prosthesis. It is relatively contraindicated if the soft tissue constraints (ligaments) are insufficient, if fixation of fractures has not been rigid, or if the elbow is unstable.

HOME USE
I believe that the use of CPM at home is as important as, or perhaps even more than, its use in the hospital. The home rental market for CPM machines is being served by at least two domestic companies at the time of this writing, so home use of CPM is practical. The typical requirement is in the range of 4 weeks for an elbow that has been stiff before surgery, and 1 to 2 weeks for elbows requiring assistance to prevent stiffness from developing.

References

1 Aldridge J.M.3rd, Atkins T.A., Gunneson E.E., Urbaniak J.R. Anterior release of the elbow for extension loss. J. Bone Joint Surg. Am. . 2004;86A:1955.
2 Breen T.F., Gelberman R.H., Ackerman G.N. Elbow flexion contractures: Treatment by anterior release and continuous passive motion. J. Hand Surg. Br . 1988;13-B:286.
3 Brown A.R., Weiss R., Greenberg C., Flatow E.L., Bigliani L.U. Interscalene block for shoulder arthroscopy: comparison with general anesthesia. Arthroscopy . 1993;9:295.
4 Gaumann D.M., Lennon R.L., Wedel D.J. Continuous axillary block for postoperative pain management. Reg. Anesth . 1988;13:77.
5 Ippolito E., Formisano R., Caterini R., Farsetti P., Penta F. Resection of elbow ossification and continous passive motion in postcomatose patients. J. Hand Surg. Am . 1999;24:546-553.
6 Kraemer W.J., Bush J.A., Wickham R.B., Denegar C.R., Gomez A.L., Gotshalk L.A., Duncan N.D., Volek J.S., Putukian M., Sebastianelli W.J. Influence of compression therapy on symptoms following soft tissue injury from maximal eccentric exercise. J. Orthop. Sports Phys. Ther . 2001;31:282.
7 O’Driscoll S.W., Giori N.J. Continuous passive motion (CPM): Theory and principles of clinical application. J. Rehabil. Res. Dev . 2000;37:179.
8 O’Driscoll S.W., Kumar A., Salter R.B. The effect of continuous passive motion on the clearance of a hemarthrosis from a synovial joint: an experimental investigation in the rabbit. Clin. Orthop . 1983;176:305.
9 O’Driscoll S.W., Kumar A., Salter R.B. The effect of the volume of effusion, joint position and continuous passive motion on intra-articular pressure in the rabbit knee. J. Rheumatol . 1983;10:360.
10 Pope R.O., Corcoran S., McCaul K., Howie D.W. Continuous passive motion after primary total knee arthroplasty. J. Bone Joint Surg. Br . 1997;79:914.
11 Remia L.F., Richards K., Waters P.M. The Bryan-Morrey triceps-sparing approach to open reduction of T-condylohumeral fractures in adolescents: Cybex evaluation of triceps function and elbow motion. J. Pediatr. Orthop . 2004;24:615.
12 Re P.R., Waters P.M., Hreski T. T-condylar fractures of the distal humerus in children and adolescents. J. Pediatr. Orthop . 1999;19:313.
13 Salter R.B. Motion vs. rest. Why immobilize joints? J. Bone Joint Surg . 1982;64-B:251.
14 Romness D.W., Rand J.A. The role of continuous passive motion following total knee arthroplasty. Clin. Orthop. . 1988;226:34.
15 Salter R.B. Motion vs. rest. Why immobilize joints? J. Bone Joint Surg . 1982;64-B:251.
16 Salter R.B., Field P. The effects of continuous compression on living articular cartilage. An experimental investigation. J. Bone Joint Surg . 1960;42-A:31.
17 Salter, R. B., McNeill, O. R., and Carbin, R.: The pathological changes in articular cartilage associated with persistent joint deformity. An experimental investigation. Studies of the rheumatoid diseases. Third Canadian Conference on Research in Rheumatic Diseases. Toronto, 1965, p. 33.
18 Schroeder L.E., Horlocker T.T., Schroeder D.R. The efficacy of axillary block for surgical procedures about the elbow. Anesth. Analg . 1996;83:747.
19 Stinson L.J., Lennon R., Adams R., Morrey B. The technique and efficacy of axillary catheter analgesia as an adjunct to distraction elbow arthroplasty: a prospective study. J. Shoulder Elbow Surg . 1993;2:182.
CHAPTER 11 Splints and Bracing at the Elbow

Bernard F. Morrey

INTRODUCTION
Elbow splints are frequently employed at the elbow and function in several capacities: protection both static and dynamic, to deliver flexion or extension torque. Specifically, the four types of braces or splints used in the postoperative and postinjury management of the elbow include resting and hinged splints, and dynamic and static adjustable splints. 10

STATIC AND PROTECTIVE SPLINTS
Prophylactic bracing is occasionally employed at the elbow, typically to avoid excessive extension in the athlete. 9 Further static splinting for the elbow is commonly used for short periods as a protective measure after injury or surgery. Previously used commonly in those with rheumatoid arthritis, largely because of the effectiveness of disease remitting agents, this type of splinting is uncommonly indicated today ( Fig. 11-1 ).

FIGURE 11-1 Resting splint rarely used for more than 2 to 3 weeks.
For the unstable elbow a hinged splint is used ( Fig. 11-2 ). By initially locking the hinge, the same device can be used as a resting static splint; some designs allow conversion to a movable stabilizing device. Hinged splints allow active motion and are employed primarily for ligament healing. Occasionally, a hinged brace is prescribed for the resected elbow, but compliance is variable, and I rarely use this type of device.

FIGURE 11-2 Hinged splint allows static support when the mechanism is locked, and active motion thereafter as desired.

ELBOW STIFFNESS
The most common complication of elbow injury, and even in some arthritic conditions, is stiffness. The most important means of avoiding this after a fracture is rigid fixation accompanied by early motion of the joint (see Chapter 22 ). After fracture dislocation, it has been demonstrated that immobilization lasting for more than 4 weeks resulted in less satisfactory outcome in each patient, 2 and despite the recognized value of early motion after injury or surgery stiffness of the elbow remains a common problem in the orthopedic practice. Unfortunately, in the author’s experience the use of aggressive physical therapy to address post-traumatic stiffness is not always successful and, in fact, as often as not, makes the contracture worse. This justifies the use of splinting in this clinical setting, but to understand the rationale of splinting for this condition, it is necessary to understand the physiology of the process.

PATHOLOGY OF ELBOW CONTRACTURE
The exact reason that the elbow is so prone to joint contracture is not known with certainty. What is recognized is that the elbow is one of the most congruous joints in the body (see Chapter 2 ). Normally, the capsule is translucent, but with insult, it undergoes a marked hypertrophy and extensive cross-linking of the fibrils, as demonstrated on scanning electron microscopy ( Fig. 11-3 ). In some instances, a severe elbow contracture has been observed after trivial insult or such as “strain” without fracture or dislocation. Under these circumstances, the elbow may contract rapidly, often within 2 to 3 weeks. An explanation of the rapid development of elbow contracture may be provided by the basic investigations on wound contracture. Experimental data demonstrate that dermal wounds undergo approximately 80% of the anticipated contracture within the first 3 weeks 1 ( Fig. 11-4 ).

FIGURE 11-3 Scanning electron microscopy (×30) showing dense hypertrophy of collagen fibrils with extensive cross-linkage sites.

FIGURE 11-4 Experimental data showing that the majority of tissue contracture occurs in the first 3 weeks.
(With permission from Billingham, R. E., and Russell, P. S.: Studies on wound healing, with special reference to the phenomenon of contracture in experimental wounds in rabbits’ skin. Ann. Surg. 144:961, 1956, p. 964.)
Continuous motion, if properly used, has been shown to be an important adjunct to successfully alter this tendency and hence prevent contracture (see Chapter 10 ).
After trauma, this modality is used with confidence, particularly if rigid fixation has been afforded to the fracture and if pain and inflammation can be controlled. After 3 to 8 weeks of treatment and if the fracture has been rigidly fixed and it is thought that force can safely be applied, the use of splints may be introduced in order to gain further motion. In general, the author’s philosophy is that continuous motion machine maintains motion but does not gain motion. The use of static adjustable splints attains motion both in flexion and in extension. The question then arises as to the best method of providing a force to stretch the periarticular soft tissues. There are four possibilities: physical therapy, continuous passive motion, dynamic splinting, and static adjustable splinting.

MANAGEMENT OF ELBOW STIFFNESS

PHYSICAL THERAPY
Physical therapy must be executed with extreme caution in the post-traumatic or inflamed elbow. The reason for this is that passive stretch, in and of itself, can introduce the very inflammation that one is trying to treat in the course of the therapy. Inflammation results in contracture and thus is an obstacle to the treatment goal. A well-trained experienced physical therapist who understands this principle can be of value, especially to assist in addressing concurrent shoulder and wrist stiffness. Such expertise is not possible in the author’s practice; therefore, I have never prescribed physical therapy for a patient of mine with elbow stiffness.

RESTORATIVE SPLINTING
Restorative splinting can be used to assist in attaining elbow motion. Splints are designed according to two diverse philosophies: dynamic or static-adjustable. To comprehend the rationale of dynamic or static adjustable splinting, some understanding of the soft tissue about the elbow as viscoelastic tissue is necessary. If thesoft tissue at the elbow can be considered viscoelastic tissue, its response to a constant versus a variable force is different. 12 The theoretical response to a constant force is shown in Figure 11-5 . This load results in soft tissue deformation, which is called creep. 8 However, what is not demonstrated in this illustration is the development of inflammation as a biologic response to this constant load. Inflammation can alter this idealized curve, and in the author’s opinion, inflammation is a common byproduct of dynamic splinting. Nonetheless, this remains an attractive option for many 11 ( Fig. 11-6 ). The alternate approach to the stiff elbow is the use of static adjustable splints. In this modality, a constant force is applied to the elbow that results in strain being imparted to the tissue. However, the force is not continuously applied, allowing stress relaxation to occur within the soft tissue sleeve over a period of time. This type of treatment has been employed extensively at the knee by serial casting and has also been effectively used at the elbow. 14 It is believed that the stress-free relaxation lessens the likelihood of inflammation, and thus, the elbow in our practice and opinion is more amenable to this type of load application ( Fig. 11-7 ). The constant force is applied so as to exceed the elastic limits of the tissue or result in a stretch. But if this load is maintained at a constant and is not further increased, tissue relaxation should occur over time. Finally, to further avoid the likelihood of inflammation, the patient controls the amount and duration of tension being applied. This is done within a very discrete set of recommendations and a very defined program (see Appendix). However, as with all torque generated across the elbow by whatever means, a compressive force is also applied to the system. This joint force can reach considerable proportions and is a function of the direction of the torque and the ankle of the elbow at the time of application 13 ( Fig. 11-8 ). Ideally, the splint hinge mechanism absorbs the majority of the force which is primarily compressive in nature whether the application is in flexion or extension.

FIGURE 11-5 Viscoelastic tissue response to a constant force resulting in gradual stretching of the tissue. The potential for inflammation, however, is not demonstrated by this curve but is possible if the force is constantly present, which is the case in dynamic loading.

FIGURE 11-6 Commercially available dynamic splint. The tension and excursion may be adjusted by the patient.

FIGURE 11-7 The tissue response to the application of a single discrete force results in stress relaxation of the viscoelastic tissue.

FIGURE 11-8 During flexion and extension variable proportions of the applied load is converted to rotatory or compressive forces at the joints.

DYNAMIC SPLINTING
Dynamic splinting has been a popular means of treating impending or developing stiffness. The concept has been used in hemophiliacs by employing a system of reverse dynamic slings at both the knee and at the elbow. 3 The earliest examples of dynamic splinting employed rubber bands to deliver to torque. At the elbow, this has given way to much more sophisticated mechanics and devices. Data has been published to suggest the value of dynamic splinting to assist extension after triceps injury. 7 Today, there are several readily available commercial devices that employ this concept (see Fig. 11-6 ). The splint is well tolerated at least initially but can cause pain and introduce reactive inflammation if used too aggressively.

STATIC ADJUSTABLE SPLINTS
The classic static adjustable splint is a turnbuckle type and use was reintroduced several years ago by Green and associates. 6 He reported an 80% success rate in treating elbow contractures from various etiologies, especially those with a major flexion contracture. Two problems were identified with the use of these splints.
As the contracture decreases to less than 30 degrees, the effectiveness of a turnbuckle to develop an extension torque decreases. Applying an extension load at this angle results in the majority of the force distributed so as to separate the hinge, and less than 25% of the force actually exerts an extension torque on the elbow ( Fig. 11-9 ). The ability of this concept to enhance post-traumatic elbow motion has been recently demonstrated in a clinical trial. 4 In another study, 11 of 22 patients gained satisfactory motion after initiating turnbuckle type bracing in a sample of those who no longer were benefiting from physical therapy. 5

FIGURE 11-9 A, With the elbow at 90 degrees, the anteriorly placed turnbuckle provides an effective force, approximately 70% of which is directed at extending the elbow and 30% in separating the joint itself. B, When the elbow is at 30 degrees, the turnbuckle is working through an angle of 15 degrees. The sine function of 15 degrees is .25. This means that 75% of the force is going to separate the hinge and distract the two components of the brace, and only 25% of the force is actually extending the elbow. These types of braces become inefficient as the elbow gets closer toward full extension.
Hence, to develop a more effective device, a means was developed to apply the force through a gear mechanism at the axis of flexion; by so doing the entire force is then applied as intended: either to extend or to flex. ( Fig. 11-10 ). The brace was designed at our institution and is termed the “Mayo Elbow Brace (Don Joy, Orthopedics) and is able to hyperextend to enhance the ability to completely resolve the contracture ( Fig. 11-11 ). However, with flexion to more than 100 or 110 degrees, the anterior soft tissue tends to bunch up, limiting further flexion. For this reason, the straps closest to the joint may be released to allow unencumbered flexion.

FIGURE 11-10 A static adjustable splint currently used by the author in which the extension torque is directly applied at the axis of rotation. Note use of air pads to distribute the local pressure exerted on the skin.

FIGURE 11-11 The same splint shown in Figure 11-10 , but reversed and being used in the flexion mode; hence, the splint is called the universal splint in our practice. For flexion the straps nearest to the hinge are released to avoid impingement.
Over the 4-year period from the introduction of this device in 2003 through 2006, we have prescribed approximately 200 braces for patients with various expressions of elbow stiffness. This experience has resulted in the application program shown in Box 11-1 and Figure 11-12 . It should be noted that an adequate amount of time should be spent with the patient to explain the rationale of the brace and specific use and goals for the specific device being used.

BOX 11-1 Basic Instructions for the Use of Static Adjustable Splints
The following general guidelines for the use of turnbuckle splints may be modified, or instructions may be given to you, depending on your individual needs and progress.

I. General Goals
• To attain improved motion of your elbow, inflammation must be avoided. This is done with the use of the anti-inflammatory agents, heat and ice, and education of the patient to the signs of inflammation.
II. Cardinal Signs of Inflammation
• Increased soreness, increased discomfort, swelling, or commonly a progressive loss of motion, rather than day-to-day improvement.
III. Treatment of Inflammation
• Avoid the causative factor. Be less vigorous with the turnbuckle splint, adhere to the heat and ice program, and take anti-inflammatory agents as prescribed. If they are inadequate, they may need to be modified. Check with us or your local doctor.
IV. Direction of Improvement
• Often, both increased elbow flexion and extension is being sought. In general, the motion that is needed most is addressed at night. The opposite motion is encouraged during the day.
V. Typical Splint Program
• On rising in the morning, the splint is removed. Gently flex and extend the elbow while taking a hot bath or shower for approximately 15 minutes. Take an anti-inflammatory agent.
• Apply the splint in a direction opposite to that which was used at night. Apply it to the point where it is recognized that the elbow is being stressed but pain is not present.
• The splint may be removed for 1 hour in the morning, 1 hour in the afternoon, and 1 hour in the evening. Reapply the splint in the opposite direction after these rest periods.
• Use the elbow when out of the splint, as able, in the evening. If the elbow is sore or seems inflamed, apply ice for 15 minutes. If the elbow is not inflamed but is stiff, apply heat for 15 minutes while gently working the joint in flexion and extension.
• On going to bed at night, apply the splint in the direction needed most. Application should be sufficiently strong so you are aware that the elbow is being stressed, and a person should be able to sleep comfortably for about 6 hours without being awakened by elbow pain.
After reading these instructions, contact your physician if you have any specific questions.

FIGURE 11-12 A sample of the daily program given to the patient at the time of splint prescription.

References

1 Billingham R.E., Russell P.S. Studies on wound healing, with special reference to the phenomenon of contracture in experimental wounds in rabbits’ skin. Ann. Surg . 1956;144:961.
2 Broberg M.A., Morrey B.F. Results of treatment of fracture dislocations of the elbow. Clin. Orthop . 1987;216:109.
3 Dickson R.A. Reversed dynamic slings: A new concept in the treatment of post-traumatic elbow flexion contractures. Injury . 1976;8:35.
4 Doornberg J.N., Ring D., Jupiter J.B. Static progressive splinting for posttraumatic elbow stiffness. J. Orthop. Trauma . 2006;20:400.
5 Gelinas J.J., Faber K.J., Patterson S.D., King G.J. The effectiveness of turnbuckle splinting for elbow contractures. J. Bone Joint Surg . 2000;82B:74.
6 Green D.P., McCoy H. Turnbuckle orthotic correction of elbow-flexion contractures after acute injuries. J. Bone Joint Surg . 1979;61A:1092.
7 Greer M.A., Miklos-Essenberg M.E. Early mobilization using dynamic splinting with acute triceps tendon avulsion. J. Hand Ther . 2005;18:365. quiz 371
8 Kottke F.J., Pauley D.L., Ptak R.A. The rationale for prolonged stretching for correction of shortening of connective tissue. Arch. Phys. Med. Rehab . 1966;47:345.
9 Lake A.W., Sitler M.R., Stearne D.J., Swanik C.B., Tierney R. Effectiveness of prophylactic hyperextension elbow braces on limiting active and passive elbow extension prephysiological and postphysiological loading. J. Orthop. Sports Phys. Ther . 2005;35:837.
10 Morrey B.F.. The use of splints with the stiff elbow. Heckman M.D., editor. Prospective in Orthopedic Surgery, Vol. I. Quality Medical Publishing, St. Louis, 1990;141. No. 1
11 Richard R., Shanesy C.P., Miller S.F. Dynamic versus static splints: A prospective case for sustained stress. J. Burn Care Rehab . 1995;16:284.
12 Richards R.L., Staley M.J. Biophysical aspects of normal skin and burn scar. In: Richard F.L., Staley M.J., editors. Burn Care and Rehabilitation: Principles and Practice . Philadelphia: F. A. Davis; 1994:65.
13 Szekeres M. A biomechanical analysis of static progressive elbow flexion splinting. J. Hand Ther . 2006;19:34.
14 Zander C.L., Healy N.L. Elbow flexion contractures treated with serial casts and conservative therapy. J. Hand Surg . 1992;17:694.
PART IV
Conditions Affecting the Child’s Elbow
CHAPTER 12 Imaging of the Pediatric Elbow

Kristen B. Thomas, Alan D. Hoffman, E. Richard Graviss

INTRODUCTION
Radiography is the primary imaging modality for evaluation of the elbow in children, as it is in adults. Although the radiographic views are the same, the pediatric patient is unique. Injury is the primary reason for evaluating the immature elbow. Children’s reactions to the process of imaging vary greatly, although they are usually related to the patient’s age and the nature of the injury sustained.
Modern radiographic equipment is a cornerstone for obtaining high-quality imaging studies. However, the most important component is a qualified radiologic technologist who understands the child’s anxieties and who has empathy for the child’s fears. Such a technologist is aware of patient and parent anxiety and that the minor motions of the elbow may cause pain. The assistance of an accompanying parent or guardian may be useful and, occasionally, is mandatory when there is insufficient technical help available for positioning. A gentle, friendly approach that is firm but reassuring will yield optimal radiographic examinations of the pediatric elbow.
The basic elbow study consists of anteroposterior and lateral views. The lateral view invariably is obtained first, because the child maintains an injured elbow in the flexed position. The patient is seated beside a radiographic table so that the arm can be elevated parallel to the level of the table top and a 90-degree flexed position can be maintained. The forearm should be supinated gently, with the thumb pointed up, positioning all three bones of the elbow in the lateral projection. The anteroposterior view then is obtained with the forearm positioned up and the elbow extended slowly as much as the injury allows. If necessary, the anteroposterior view can be divided into two segments: one with the humerus parallel to the radiographic film, and the other with the forearm parallel to the radiographic film. This provides better anatomic detail than does a single exposure with the elbow partially flexed and neither component parallel to the film.
Some unstable fractures and dislocations require splinting such that views obtained at right angles are usually sufficient for the initial diagnosis. The fracture or dislocation with obvious clinical deformity is usually less problematic than is the subtle fracture, which may go undetected. When the patient is examined for subtle fractures, the lateral view is extremely important, and positioning should be flawless. This view provides clues concerning the injured elbow, such as the anterior and posterior fat pad signs. It also allows for visual alignment of the distal humeral ossification segments with the shaft of the humerus and with the radius.
In certain instances, a fluoroscopic examination of the elbow may yield valuable information. The examiner can manipulate the elbow to obtain the precise obliquity required to best evaluate a subtle abnormality. Instead of repeating a radiograph multiple times, optimal positioning can be obtained while watching real-time fluoroscopy and then digital fluoroscopic spot radiographs are easily taken.
Tomography, using either a simple linear method or a complex motion system, can be used in the evaluation of growth plates that have closed prematurely following trauma. In most practices, computed tomography has completely replaced conventional tomography. Computed tomography examinations now take only seconds to perform, and sedation is usually not necessary, even in very young infants and children. Using current 64-slice multidetector computed tomography technology (MDCT), isovoxel images can be obtained in all three planes down to 0.6-mm collimation. This allows detailed imaging, with the bony trabecular pattern well seen. Examinations are obtained with the patient in the prone position, with the affected arm held above the head with about 90 degrees of flexion at the elbow. Sagittal and coronal two-dimensional reformatted images as well as three-dimensional reconstructions are then made from the raw data. MDCT is a sensitive (92%) and specific (79%) method of evaluating for radiographically occult elbow fractures. 6 MDCT can also use automated tube current modulation to markedly decrease the radiation dose to the patient compared with fixed-tube current techniques. MDCT can also be performed with no image degradation through a cast. 3 MDCT with reformatting can better delineate intra-articular fractures ( Fig. 12-1 ). Three-dimensional imaging can also provide additional information and help define the joint relationships to aid surgical planning ( Figs. 12-2 and 12-3 ). The resulting three-dimensional image can be rotated in all planes with computerized subtraction of the adjacent soft tissues and bones, if needed.

FIGURE 12-1 Computed tomography two-dimensional reformatted coronal image of intra-articular distal humeral intercondylar fracture in a 13-year-old boy who was injured while skateboarding.

FIGURE 12-2 Computed tomography three-dimensional reconstruction of a complex intra-articular distal humeral fracture from the posterior view in a 14-year-old boy injured while playing basketball.

FIGURE 12-3 Magnetic resonance imaging of a 13-year-old boy with elbow pain, coronal ( A ) and sagittal ( B ) views. T1-weighted images show a defect in the capitellum. No loose body is seen. The clinical diagnosis was Panner’s disease, and symptoms resolved in a few months without specific therapy.
Magnetic resonance imaging (MRI) and ultrasonography are increasingly being used to evaluate the elbow. MRI can evaluate cartilage, bone marrow, and soft tissue structures ( Fig. 12-4 ). 8 Radiographs do not show bone bruising, or cartilaginous or soft tissue injury and can underestimate physeal injury. MRI is also occasionally used to better define elbow fractures. 2 Owing to the length of the MRI examination (at least 20 minutes), children younger than 5 years old will usually need sedation so that optimal MRI images can be obtained. In children with elbow trauma, MRI reveals a broad spectrum of bone and soft tissue injury, including ligamentous injury, beyond that recognized by radiographs. However, the additional information afforded by MRI usually does not change treatment or clinical outcome in acute elbow trauma. 9 MRI can be very useful in the evaluation of osteochondritis dissecans (OCD) of the capitellum. MRI provides information about the size, location and stability of the OCD lesion. All of these factors are important when deciding treatment options (see Chapter 20 for more discussion). Unstable OCD lesions in the capitellum have a peripheral rim of high signal or an underlying fluid-filled cyst on T2-weighted images ( Fig. 12-5 ). Stable OCD lesions have no peripheral signal abnormality. 12 Loose bodies in the elbow joint can be visualized by MRI or MDCT, but smaller detached bone fragments are usually better visualized using MDCT ( Fig 12-6 ).

FIGURE 12-4 Computed tomography three-dimensional reconstruction of an 11-year-old boy with the clinical diagnosis of Panner’s disease. Several small loose bodies are seen adjacent to the capitellum.

FIGURE 12-5 Magnetic resonance imaging (T2 sagittal image) of a 12-year-old boy demonstrates osteochondritis dessicans (OCD) of the capitellum with increased signal extending to the articular surface consistent with full-thickness cartilage loss. This indicates a potentially unstable OCD bone fragment that has not yet detached. A moderate elbow joint effusion is also present.

FIGURE 12-6 Computed tomography axial image of a 12-year-old female gymnast demonstrates a small intra-articular loose body within the posterior elbow joint (arrow) secondary to osteochondritis dissecans of the capitellum. The tiny bone fragment was not visible on radiographs.
Ultrasonography has the ability to dynamically delineate soft tissues and cartilage in detail. 13 Soft tissue swelling, a mass (including vascular masses investigated with duplex Doppler and color flow Doppler), joint effusion, and fractures, particularly in infants and young children with unossified or minimally ossified epiphyses, are studied with this modality. 1, 7 Ultrasound can detect early changes of medial epicondylar fragmentation and OCD of the capitellum, even in the asymptomatic stage in selected populations such as young baseball players. 10
As with other portions of the appendicular and axial skeletons, side-to-side comparison may be helpful when one is presented with an unfamiliar or a rare variant. Comparison views need to be obtained only in selected cases, 14, 15 such as when consultation with the standard text of normal cases is not helpful. 5, 11, 17

NORMAL DEVELOPMENT
The maturation sequence at the elbow is more variable than that of the hand and wrist. Nonetheless, an appreciation of the normal sequence and timing of the appearance of ossification centers and maturation patterns is important for an understanding of the radiographic appearances of the elbow in children ( Fig. 12-7 ). Several mnemonics have been suggested to help remember the time of appearance of the ossification of these centers. We find that the cross-connecting ossification centers (see Fig. 12-7B ) are particularly helpful in remembering at least the order of ossification of these centers. An atlas entitled Radiology of the Pediatric Elbow 5 shows standards for elbow maturation in children. To consistently evaluate the developing elbow, one must analyze each of the secondary centers of ossification, accounting for its appearance, configuration during development, and associated changes as it matures and eventually fuses with the humeral shaft. The descriptions that follow are brief, but they outline the major points of development and maturation of the centers.

FIGURE 12-7 A, Normal left elbow showing the secondary centers: capitellum (c); medial epicondyle (m); radial head (r); trochlea (t); olecranon (o); and lateral epicondyle (l). B, The approximate age at time of appearance of these centers is indicated in years. The cross connecting the secondary centers of the distal humerus serves as a reminder of the order of ossification of these centers.
(Modified from Brodeur, A. E., Silberstein, M. J., Graviss, E. R., and Luisiri, A.: The basic tenets for appropriate evaluation of the elbow in pediatrics. Curr. Probl. Diagn. Radiol. 12:1, 1983.)

CAPITELLUM
The capitellum, the first of the elbow’s six centers to ossify, generally becomes radiographically visible during the first and second years of life. Initially spherical, it flattens posteriorly to conform to the adjacent distal end of the humerus. The physis is broader posteriorly than anteriorly, giving the capitellum the appearance of a downward tilt; however, this appearance gradually disappears during the first decade ( Fig. 12-8 ). During maturation, the capitellum fuses with the trochlea and the lateral epicondyle before it unites with the humeral shaft ( Fig. 12-9 ).

FIGURE 12-8 Lateral elbow radiograph of a 2.5-year-old girl. A line along the anterior humeral shaft normally intersects the posterior half of the middle third of the capitellum. The continuation of the curved coronoid line just touches the anterior edge of the ossified capitellum. The angle formed by the coronoid line and humeral shaft line should contain the majority of the ossified capitellum.

FIGURE 12-9 A 13-year-old girl in whom the capitellum has joined with the lateral epicondyle and trochlea before fusion with the humeral shaft. Note the normal sclerotic radial epiphysis that is wider than the radial neck.
The orientation of the capitellum with the humerus can be evaluated with a true lateral projection. The anterior surface of the humerus is gently bowed posteriorly, from the insertion of the deltoid muscle to the superior aspect of the coronoid fossa. A line drawn along the anterior surface of the humerus, from the deltoid insertion to the top of the coronoid fossa, should pass through the middle third of the capitellum. For practical reasons, most lateral examinations of the elbow do not include the deltoid insertion; therefore, one must use the most proximal portion of the humerus included on the radiograph. These two points determine the anterohumeral line, which passes precisely through the posterior half of the middle third of the capitellum. The capitellum is oriented anteriorly to the distal humerus. One also may draw a curvilinear line along the coronoid fossa. The extension of that line inferiorly should touch the anterior portion of the capitellum.
These two lines permit the detection of subtle supracondylar fractures, particularly Salter-Harris type I supracondylar fractures, with minimal posterior displacementof the distal humeral epiphysis with the capitellar ossification center.

RADIOCAPITELLAR LINE
The radiocapitellar line is a line drawn through the long axis of the proximal radial shaft that should, in the absence of dislocation, pass through the middle of the capitellum ossification center. This is generally true in anteroposterior, lateral, or any oblique projection. In early development, however, the radial metaphysis is wedged so that on the anteroposterior projection a normal radial shaft line may appear to extend laterally to the capitellum. However, on the lateral projection, the normal radiocapitellar line can be appreciated ( Fig. 12-10 ). In older patients, although it may appear that the radiocapitellar line is normal in one projection in a patient with a radial head dislocation, it invariably will be abnormal in the projection taken at right angles, generally the lateral projection. 18

FIGURE 12-10 A, Normal 7-month-old girl with apparent abnormal radiocapitellar line on the anteroposterior radiograph because of wedging of the metaphysis. B, The relationship between the radial shaft and capitellum is normal on the lateral radiograph.

MEDIAL EPICONDYLE
The medial epicondyle is the second elbow ossification center to appear in the normal sequence, usually at about 4 years. Lying posteromedially, it is often best appreciated on the lateral projection ( Fig. 12-11 ). Frequently, it develops from more than one ossific nucleus. Although it is the second humeral ossification center to appear, its development is slow, and it is usually the last center to unite with the humeral shaft in the normal child, sometimes as late as 15 or 16 years of age. 20 This center may fuse with the trochlea before uniting with the humeral shaft. Injuries involving the nonunited medial epicondyle are relatively common and are among the most difficult to evaluate. Consequently, to avoid errors, Rodgers suggests making a habit of identifying the presence and the position of the medial epicondyle ossification center in each case. 16 A classic example of the importance of appreciating the sequence of humeral ossification center appearance is avulsion and displacement of the medial epicondyle ossification center. This frequently results in the displacement of the medial epicondyle into the normal position of the trochlear ossification center. In a child between 4 and 8 years of age, at the time of appearance of the medial epicondyle and the trochlear ossification centers, a radiograph suggesting a trochlear ossification center, without visualization of a medial epicondyle center, should suggest that fracture and dislocation of the medial epicondyle have in fact occurred. 13

FIGURE 12-11 A, A 10-year old boy with a normal posteromedially lying ossification center for the medial epicondyle (arrows) seen posterior to the humeral shaft on the lateral projection. B, Another 10-year-old boy who sustained trauma resulting in avulsion of the medial epicondyle, which is displaced anteriorly (arrows) on the lateral projection, and displaced medially ( C ), and rotated on the anteroposterior projection.

RADIAL HEAD EPIPHYSIS
The initial ossification of this epiphysis is fairly predictable and usually occurs in the fifth year (see Fig. 12-7B ). Although usually beginning as a sphere, the radial head epiphysis often matures as one or more flat sclerotic centers. This pattern may be mistakenly interpreted as a fracture. With maturation, the physis on the anteroposterior radiograph is wider laterally than medially, and this appearance, combined with the medial angulation of the radius at the junction of its shaft and neck, may suggest dislocation on anteroposterior views. Lateral projection of the elbow will not confirm a suspected dislocation. With further maturation of ossification of the proximal radial ossification center, the normal relationship of the radius and capitellum can be seen on anteroposterior radiographs. Notches or clefts of the metaphysis of the proximal radius often are seen as normal variations of ossification during maturation. 11, 17
Because fractures of the radial neck are extracapsular, they are not associated with hemarthrosis and abnormalities of the humeral fat pads. 19

TROCHLEAR EPIPHYSIS
Ossification of the trochlea appears at about 8 years and often is initially multicentric ( Figs. 12-12 and 12-13B ). The trochlea frequently maintains an irregular contour during its development and should not be confused with abnormal processes such as trauma or avascular necrosis ( Fig. 12-14 ). The trochlea will fuse with the capitellum before fusion with the distal humeral shaft. It is seldom fractured, except when associated with the vertical component of a supracondylar fracture or when its lateral edge is involved with a lateral condylar fracture.

FIGURE 12-12 Multiple ossification nuclei of developing trochlea (arrow) in a 9-year-old boy.

FIGURE 12-13 A, Lateral radiograph with lucent region in the proximal radial shaft (arrows). B, Anteroposterior view shows prominent but normal radial tuberosity (arrow) . Residual changes from previous transcondylar fracture of the humerus are seen.

FIGURE 12-14 A 9-year-old boy with beginning ossification of the lateral epicondyle (arrow) from a thin sliver widely separated from the metaphysis. Note the irregular outline of the developing ossification center of the trochlea.

OLECRANON
The ossification center of the olecranon usually develops at 9 years of age, shortly after the trochlea and just before the lateral epicondylar epiphysis. The proximal end of the ulna flattens and becomes sclerotic just before the olecranon physis ossifies. Two ossification centers most often develop, and there is great variability in the configuration of the epiphysis. This results in an occasional misdiagnosis of acute fracture. The posterior ossification center is usually bigger than the anterior ossification center ( Fig. 12-15 ), and these separate centers generally unite before fusion with the proximal humerus. This process usually begins at about 14 years of age.

FIGURE 12-15 A 13-year-old boy with double ossification center of the olecranon. The anterior nucleus is smaller.
The pattern of closure of the olecranon physis is distinct, with fusion occurring first along the joint line and then extending posteriorly. Frequently, fractures are wedged in the opposite direction. 21
The olecranon physis has prominent sclerotic margins just before closure. Fusion proceeds posteriorly from the joint side or the anterior surface ( Fig. 12-16 ). During its development, the physeal line remains relatively perpendicular to the ulnar shaft. As a result of differential growth, often with maturation, the olecranon growth plate, which initially is proximal to the elbow joint, comes to lie at a midelbow joint level by the time of fusion. This “wandering physeal line of the olecranon” does not occur in all individuals. 4

FIGURE 12-16 A 14-year-old male in whom closure of the olecranon growth plate has begun anteriorly. Note the sclerotic margin of that portion of the growth plate that remains unfused.
Although the majority of olecranon fractures are intracapsular and are associated with alterations of fat pads, some are not. The tip of the olecranon is not within the capsule in some individuals. The only other common site of fracture related to the elbow that lies outside the joint capsule is the radial neck (see Chapter 17 ). 4

LATERAL EPICONDYLE
The ossification center of the lateral epicondyle is the last of the elbow centers to appear. Usually, this center is first seen at 10 or 11 years of age, and it fuses to the humeral shaft at about 14 years of age. Unlike the other ossification centers of the elbow, the lateral epicondyle appears first as a thin sliver rather than as a round or spherical ossific nucleus (see Fig. 12-14 ).
Ossification commences at the lateral portion of the cartilaginous mold so that the physis appears particularly wide. The inferior aspect of the ossification begins at the junction between the distal humerus and the capitellum. 5
Because of the relatively short time between the appearance and fusion of this center, it is not always certain in individual cases whether ossification is delayed or fusion to the humerus already has occurred. To avoid confusion about this point, it must be realized that before ossification, the humerus has a sharp, straight, sloping metaphyseal line that changes to a sloping, curving margin at the capitellum. The fused lateral epicondyle, on the other hand, has a smooth, curved margin that is continuous with the capitellum ( Fig. 12-17 ).

FIGURE 12-17 A, A 9-year-old boy in whom ossification of the lateral epicondyle is about to begin. The metaphysis has a sharp, straight, sloping margin. B, The fusing lateral epicondyle in this 14-year-old boy, in contrast, has a smoother, rounded margin.

NORMAL VARIANTS
In addition to the confusing appearances caused by the normally developing elbow, there are a few variations from normal or unusual appearances that should be noted.
The radial tuberosity lies medially at the junction of the medial shaft and the neck. On lateral views, it may appear as an undermineralized focus and may be misinterpreted as a destructive lesion of the bone (see Fig. 12-13 ). On the anteroposterior view of the elbow, the thin humeral olecranon fossa occasionally appears to be entirely lucent, the so-called perforated olecranon fossa ( Fig. 12-18 ). In some instances, there is a bridge of bone crossing or a separate ossicle within a perforated olecranon fossa.

FIGURE 12-18 A 6-year-old boy with perforated olecranon fossa. There has been a previous supracondylar fracture.
A rare anatomic anomaly is a bony projection from the anterior medial distal humerus known as the supracondylar process ( Fig. 12-19 ), which is discussed in Chapter 2 .

FIGURE 12-19 Supracondylar process in a mature elbow. Anteroposterior ( A ) and lateral ( B ) radiographs.

References

1 Barr L.L. Elbow. Clin. Diagn. Ultrasound . 1995;30:135.
2 Beltran J., Rosenberg Z.S., Kawelblum M., Montes L., Bergman A.G., Strongwater A. Pediatric elbow fractures: MRI evaluation. Skeletal Radiol . 1994;23:277.
3 Blickman J.G., Dunlop R.W., Sanzone C.F., Franklin P.D. Is CT useful in the traumatized pediatric elbow? Pediatr. Radiol . 1990;20:184.
4 Brodeur A.E., Silberstein M.J., Graviss E.R. Radiology of the Pediatric Elbow. Boston: G. K. Hall, 1981.
5 Brodeur A.E., Silberstein M.J., Graviss E.R., Luisiri A. The basic tenets for appropriate evaluation of the elbow in pediatrics. Curr. Probl. Diagn. Radiol . 1983;12:1.
6 Chapman V., Grottkau B., Albright M., Elaini A., Halpern E., Jaramillo D. MDCT of the elbow in pediatric patients with posttraumatic elbow effusion. A. J. R . 2006;187:812.
7 Davidson R.S., Markowitz R.I., Dormans J., Drummond D.S. Ultrasonographic evaluation of the elbow in infants and young children after suspected trauma. J. Bone Joint Surg . 1994;76A:1804.
8 Gordon A.C., Friedman L., White P.G. Pictorial review: Magnetic resonance imaging of the paediatric elbow. Clin. Radiol . 1997;52:582.
9 Griffith J.F., Roebuck D.J., Cheng J.C.Y., Chan Y.L., Rainer T.H., Ng B.K., Metreweli C. Acute elbow trauma in children: Spectrum of injury revealed by MR imaging not apparent on radiographs. A. J. R . 2001;176:53.
10 Harada M., Takahara M., Sasaki J., Mura N., Ito T., Ogino T. Using sonography for the early detection of elbow injuries among young baseball players. A. J. R . 2006;187:1436.
11 Keats T.E. An Atlas of Normal Roentgen Variants That May Simulate Disease, 5th ed., St. Louis: Mosby-Year Book; 1992:395.
12 Kijowski R., De Smet A.A. MRI findings of osteochondritis dissecans of the capitellum with surgical correlation. A. J. R . 2005;185:1453.
13 Markowitz R., Davidson R.S., Harty M.P., Bellah R.D., Hubbard A.M., Rosenberg H.K. Sonography of the elbow in infants and children. A. J. R . 1992;159:829.
14 McCauley R.G.K., Schwartz A.M., Leonidas J.C., Darling D.B., Bankoff M.S., Swan C.S.2nd. Comparison views in extremity injury in children: an efficacy study. Radiology . 1979;131:95.
15 Merten D.F. Comparison radiographs in extremity injuries of childhood: current application in radiological practice. Radiology . 1978;126:209.
16 Rodgers L.F. Radiology of Skeletal Trauma. New York: Churchill Livingstone, 1982;435.
17 Schmidt H., Freyschmidt J. Köhler/Zimmer Borderlands of Normal and Early Pathologic Findings in Skeletal Radiology, 4th ed. New York: Thieme Medical Publishers, 1993.
18 Silberstein M.J., Brodeur A.E., Graviss E.R. Some vagaries of the capitellum. J. Bone Joint Surg . 1979;61A:244.
19 Silberstein M.J., Brodeur A.E., Graviss E.R. Some vagaries of the radial head and neck. J. Bone Joint Surg . 1982;64A:1153.
20 Silberstein M.J., Brodeur A.E., Graviss E.R., Luisiri A. Some vagaries of the medial epicondyle. J. Bone Joint Surg . 1981;63A:524.
21 Silberstein M.J., Brodeur A.E., Graviss E.R., Luisiri A. Some vagaries of the olecranon. J. Bone Joint Surg . 1981;63A:722.
CHAPTER 13 Congenital Abnormalities of the Elbow

Peter C. Amadio, James H. Dobyns

INTRODUCTION
Elbow function and configuration are affected by conditions both proximal and distal to the elbow as well as abnormalities at the elbow itself. With this proviso, this chapter discusses congenital anomalies of the region between the shaft-metaphyseal junction of the humerus proximally and the bicipital tuberosity distally, and reviews the current state of knowledge for evaluation and treatment in that region.

CAUSES OF CONGENITAL ANOMALIES
The causes of congenital elbow anomalies follow the same patterns of genetic or somatic damage to the embryo that are seen in other congenital anomalies. Often the most difficult problem is to decide whether the presenting deformity is entirely congenital or perhaps developmental or possibly even traumatic, and whether one or more of these etiologies are interacting. The most common condition in which this difficulty arises, radial head subluxation or dislocation, may be congenital, developmental, or post-traumatic. If it is not present at birth, it may be induced by a relatively trivial injury or merely by a short ulna from any cause. Because so much of the elbow area is cartilaginous at birth, it is difficult to rule out trauma as a possible agent in some dislocations and deformities. In addition, infections, tumors (congenital or infantile), and diseases (e.g., hemophilia) occasionally involve the elbow and may simulate congenital anomaly.
Conditions that commonly involve the elbow are constitutional diseases of bone, metabolic abnormalities, and syndromes featuring limb formation and differentiation failures 36, 38, 43, 54, 82, 90 ( Table 13-1 ). Some of the syndromes can be grouped under broad categories such as osteochondrodysplasia, 3, 29, 33, 90 dysostoses, 18 primary growth disturbances, primary metabolic abnormalities, and congenital myopathies. Most, however, are chromosomal syndromes, from the common dislocation of the radial head 69 through fairly well-known syndromes such as trisomy 18, fibrodysplasia ossificans progressiva and the Antley-Bixler syndrome 7 to such rarities as the Bruck syndrome (osteogenesis imperfecta with congenital joint contractures) and a congenital mirror movement syndrome. In some cases, the specific gene locus has now been identified; for example, elbow synostosis may also occur in the context of the multiple synostosis syndrome, 53 which has been reported in large family groups and is the result of mutations in genes controlling TGF-b synthesis, including noggin, a protein believed to be important in establishing morphogenic gradients.

TABLE 13-1 Elbow Deformities in Congenital Syndromes




CLASSIFICATION
A multitissue defect classification can be based on the most obvious and most inhibiting tissue defect known to be present. Some degree of defect in other tissues is also commonly noted. The classification consists of three major categories: (1) bone and joint anomalies, (2) soft tissue anomalies, and (3) anomalies involving all tissues. Bone and joint abnormalities at the elbow may include major absences, but more commonly the skeletal structures are present but malformed. The common bone and joint problems are synostosis ( Fig. 13-1 ), ankylosis ( Figs. 13-2 to 13-4 ), and instability ( Fig. 13-5 ). Soft tissue anomalies include malformations with contractures, control deficiencies, isolated tissue anomalies ( Fig. 13-6 ), and congenital tumors ( Fig. 13-7 ). Complete absence or disorganization of the whole limb, including elbow structures, may occur, as in phocomelia ( Fig. 13-8 ); usually, recognizable though dysplastic structures are present ( Fig. 13-9 ). Similar involvement, although more isolated to the elbow area, occurs in the pterygium syndromes.

FIGURE 13-1 A, Lateral and ( B ) anteroposterior x-ray views of a hypoplastic distal humerus and an apparent radial head subluxation certainly reveal a deformity but probably not a subluxation. Clinically, there was no evidence of a dislocated radial head. C, The opposite elbow showed a radiohumeral synostosis and also a recent fracture just proximal to the synostosis. This case demonstrates the difficulties of differentiation between subluxation, dislocation, and synostosis about the elbow, but the etiology is clearly congenital.

FIGURE 13-2 This anteroposterior view of an elbow in congenital ulnar dimelia shows no radiohumeral joint but two ulnohumeral joints. The appearance is unusual as expected, but no dislocation is noted. Motion of the elbow and forearm is limited by more than 50%.

FIGURE 13-3 A, Elbow and forearm function are, to date, nearly normal in this teenage boy in whom the anteroposterior x-ray view shows ulnar hypoplasia and bowing, distortion of the distal ulnar physis-metaphysis, and subluxation of the radial head. B, The lateral x-ray view shows a similar epiphysis-physis-metaphysis distortion of the proximal ulna with associated joint surface irregularity and shaft bowing. No diagnosis has been confirmed, but this is probably an osteochondrodysplasia. The elbow abnormalities are developmental.

FIGURE 13-4 A, This 18-month-old infant with chondrodysplasia punctata has developmental contractures of many joints including the elbows, where broad metaphyses and irregular, calcified epiphyses ( B ) are seen.

FIGURE 13-5 This case further demonstrates the overlap between congenital and developmental abnormalities of the elbow. Gradual radial head subluxation due to unequal length of forearm bones is well known in multiple exostosis. These anteroposterior and lateral x-rays demonstrate a severe dislocation of the radial head that was present at birth and was associated with a severe osteochondroma deformity of the distal ulna with inhibition of ulnar growth.

FIGURE 13-6 A, Congenital aplasia of skin and soft tissues at the elbow and proximal forearm results in ( B ) developmental bone changes in the forearm and elbow.

FIGURE 13-7 A, The anteroposterior (AP) and lateral x-rays of the elbow and forearm in a patient with juvenile fibromatosis reveal marked enlargement of the ulna, posterolateral subluxation of the radial head, moderate enlargement of the distal humerus, and surface irregularities at all aspects of the joint. The changes in the elbows are developmental. B, A much more typical congenital posterior radial head dislocation is revealed in these AP and lateral views (A) and (B) of the elbow of a 14-year-old male with nail-patella syndrome and restricted elbow-forearm motion: 30 to 155 degr7es flexion extension; 45 degrees supination; 60 degrees pronation. His mother has the same diagnosis and the same problem.

FIGURE 13-8 This radiograph of the upper limb of a patient with congenital phocomelia shows a fairly well-developed shoulder and arm, a very hypoplastic hand, and fusion of all elbow elements with the short ulna protruding at right angles to the radius and forearm.

FIGURE 13-9 A, In another instance of generalized congenital hypoplasia of the upper limb, all segments from the shoulder girdle through the hand are equally and severely affected. B, Synostosis of all components of the elbow is present ( C ), correlated with a hypoplastic and asymmetric forearm plus a hypoplastic hand. D, Hypoplasia of the arm, shoulder, and shoulder girdle is also obvious on this radiograph.
With reference to the bone and joint deformities only, it has been useful to many authors to classify them as congenital, developmental, or post-traumatic. As noted earlier, there is much confusion and interplay between these diagnoses, particularly with reference to radial head subluxation or dislocation. In this classification, congenital refers to a primary genetic dysplasia of the skeletoarticular structure of the elbow, resulting in an observed deformity. Other congenital anomalies or a familial history of similar anomalies help confirm this as an etiology. Developmental refers to elbow skeletal structures that are relatively normal at birth but that are then secondarily deformed by abnormal stresses (perhaps from a congenital shortening of the ulna); by paralysis or other limited motion (arthrogryposis); neural, metabolic, endocrine or dyscrasia disturbances (hemophilia, loss of pain recognition, hemochromatosis, and so on); tumor or hamartomatous involvement (fibromatosis, osteochondromata, and so on), and disease (sickle cell anemia, Gorham’s disease, infections). The post-traumatic etiologic grouping is included in this chapter only because of the continuing confusion over early radial head dislocations, which are often post-traumatic, either as a variant of Monteggia fracture dislocation or as a pure dislocation of the soft cartilaginous radial head pulling through the annular ligament (see Chapter 20 ) and its residua.
Both early and late, dislocation of the radial head is often diagnosed as a congenital subluxation or dislocation, but it often is not. A radial head subluxation or dislocation in an elbow with normal, neural, muscular, and skeletal structures in both elbow and forearm is post-traumatic until proven otherwise; such an elbow with abnormal skeletal forearm structures is probably due to developmental stresses, but additional trauma may play a part. Such an elbow with a synostosis from birth or other skeletal deformity and no evidence of peri-birth trauma is due to congenital causes, but again, trauma may be an additional factor. The confusions highlighted by this classification have been much discussed in the literature. 14, 20, 38, 45, 51, 54, 61, 70, 71, 72, 79

DIAGNOSIS

BONE AND JOINT ANOMALIES

Synostosis
Synostoses may occur between all or any two of the three bones present at the elbow. The most common synostosis is that between the radius and the ulna proximally in the forearm, near the elbow ( Fig. 13-10 ), but these two bones also may be joined at any point in their paired course in the forearm. Mital 55 has classified these synostoses as type I, proximal to the proximal radial physis, and type II, distal to the proximal radial physis. Type II synostoses are more likely to be associated with congenital dislocation of the radial head. 45 Cleary and Omer 12 suggested a four-level classification scheme, in which Type I is clinically but not radiographically fused with a reduced normal-appearing radial head; Type II is similar but with a clear, bony synostosis; Type III has a hypoplastic posteriorly dislocated radial head; and Type IV has a hypoplastic anteriorly dislocated radial head. Type III appears to be the most common deformity and the one most likely to be associated with significant rotational deformity (almost always pronation). In addition, radiohumeral synostosis, ulnohumeral synostosis, or synostosis among the radius, humerus, and ulna may be present; often, the synostosis is in association with other limb abnormalities, the most common of which is probably ulnar deficiency. 30, 31, 42, 57, 84 Synostosis may also be associated with fetal alcohol syndrome. 84 Incomplete synostosis may occur, but often, this is a radiologic appearance rather than an actual occurrence, because complete radiographic synostosis is usually present by maturity. 27, 38, 50, 82 Cleary and Omer’s five cases of type I synostosis are, however, genuine; all of the patients were skeletally mature at the time of final clinical and radiologic review. 12

FIGURE 13-10 A, X-ray view of a typical congenital proximal, radioulnar, synostosis. B, The lateral view of the same synostosis is seen but demonstrates no radial head posterior subluxation, although this is commonly seen. C, Oblique view of the typical congenital radiohumeral synostosis of the Antley-Bixler syndrome.
Synostosis between the humerus and either the radius, ulna, or both is less common. Of these, the humeroradial type is most common, followed by humeroradioulnar and humeroulnar types. 52 However, anatomy is not the whole story, and McIntyre and Benson 52 have proposed an etiologic classification of developmental elbow synostoses, specifically as to whether the synostosis occurs with (class I, or bony type) or without (class II, or joint type) limb hypoplasia. Within each class, the synostosis can be further characterized as occurring in a sporadic or familial pattern and, if familial, with dominant or recessive inheritance. In familial cases, the condition is usually bilateral. 12 One of the more dramatic presentations is in the Antley-Bixler syndrome, an autosomal recessive disorder characterized by radiohumeral synostosis, cranial synostosis, midface hypoplasia, and a variety of urogenital and cardiac abnormalities ( Fig. 13-10C ). 7 Distal radioulnar dislocation is a common accompaniment of many of these syndromes.

Ankylosis
Partial ankylosis of the elbow or the proximal radioulnar joint is often overlooked because limited elbow-forearm motion is common in infancy 28 and often not remarked in childhood. Causes include failure of complete synostosis, intrinsic abnormalities of the joint or surface formation mechanism, and abnormalities of the surrounding soft tissues, as occurs in pterygium cubitale. The joint must be formed correctly, must have adequate surface material and ligamentous support, and must move soon after its formation, or it will become ankylosed, as occurs, for example, in arthrogryposis, or, far more rarely, in Apert’s syndrome. 35, 89 There are instances when all or part of the elbow appears to be dislocated but proves to be only malformed and limited in motion ( Fig. 13-11 ). Patients with dysplasia, such as those with Apert’s syndrome, may show a progressive loss of motion over time. 89

FIGURE 13-11 A, Anteroposterior (AP) x-ray view of an apparent radiohumeral dislocation similar to that shown in Figure 13-2 is seen preoperatively. B, A postoperative AP x-ray view 4 years later shows repositioning of what was determined to be a congenital displaced radiohumeral joint without a dislocation of the radial head. C, A lateral postoperative view of the same elbow. Repositioning was obtained when the radius was shortened by removing a segment of the radial shaft. This segment of excised radius was then used to block the repositioned lateral condyle in its new position. This surgical procedure improved the x-ray position of the elbow but did not change function, which demonstrated both preoperatively and postoperatively mild loss of extension-flexion and moderate loss of supination-pronation.

Instability
True congenital elbow instability seldom resembles the post-traumatic condition, but the two are often mistaken for each other. Congenital ulnohumeral dislocation is infrequent except in severe multitissue hypoplasia such as phocomelia, severe ulnar hypoplasia, and severe pterygium syndrome.
The most common problem of instability at the elbow is that of radial head subluxation or dislocation. 1, 2, 11, 20, 22, 25, 38, 47, 48, 61, 64, 67, 78, 79 When subluxation is an isolated phenomenon, there is considerable doubt about whether it is congenital, developmental, or post-traumatic. 14, 20, 38, 45 ,51 The pulled elbow of infancy is a well-known clinical problem that is associated with trivial trauma and laxity or minor tears of the annular ligament. 61 ,70 ,72 ,75 Children have been seen at birth or shortly thereafter with similar problems. 14, 61, 75 Furthermore, such subluxations in the infant, if not treated by closed reduction or other means, may result in deformities similar to those described as indicative of congenital dislocation of the radial head. It has been said that the degree of deformity in the few cases of known infantile dislocation that have been left untreated but followed suggest that the resulting deformity is milder than that seen in definite congenital hypoplasia at the elbow. This may be so but the so-called criteria for classifying a radial head dislocation as congenital (see later) may be seen after any early radial head dislocation regardless of cause ( Fig. 13-12 ). By contrast, when traumatic dislocation is unreduced in the older child, the development of the radial head and the capitellum remains fairly normal, displaying only minimally those radiographic features said to be characteristic of congenital radial head dislocation. These features are (1) a dislocated or subluxed radial head, (2) an underdeveloped radial head, (3) a flat or dome-shaped radial head, (4) a more slender radius than normal, (5) a longer radius than normal, (6) an underdeveloped capitellum humeri, and (7) a lack of anterior angulation of the distal humerus. 4, 20, 56, 63, 88 Bilaterality, especially symmetric bilateral dislocation, is usually also considered evidence of a congenital etiology, but this is not an absolute requirement. 48 However, many if not all the features of congenital dislocation can also be seen with developmental dislocation, due to mild degrees of ulnar or capitellar hypoplasia. In such cases the radial head may slowly dislocate with growth, as the paired forearm bones continue to grow at dissimilar rates. 4

FIGURE 13-12 Anterior dislocation of the radial head is demonstrated at initial diagnosis (age 2 weeks), at age 4 months, and at age 11 years. In addition to the dislocation, there is a reversal of the ulnar curve and some convexity of the radial head. The etiology is probably post-traumatic.
There may be only one absolute criterion of congenital elbow dislocation—dislocation with severe hypoplasia of all the osseous elements of the elbow. Absence of the capitellum is probably an example of congenital aplasia, but hypoplasia of the capitellum may occur after dislocation from any cause, as may a deformity of the radial head (see Chapter 20 ).
When radial head dislocation is familial, bilateral, or seen at birth, or when it occurs with other musculoskeletal anomalies, particularly anomalies in the same upper limb, the evidence is strong that the radial head dislocation is congenital. Cases that are diagnosed later in life may be associated with a discrepancy in length of the paired forearm bones and, therefore, may fall within the “developmental” category. It is well known that inadequate length of the ulna from any cause will result in increased compressive stresses along the radius, gradually leading to a subluxation and perhaps a dislocation of the radial head. 38, 47, 79 Such subluxations, therefore, also may be a secondary phenomenon. 48
Approximately half of all patients with isolated congenital radial head dislocation will have a problem bilaterally. 2, 48, 56 Bell and associates 4 have classified isolated congenital dislocations of the radial head as type I, subluxation; type II, posterior dislocation with minimal displacement; and type III, posterior dislocation with significant proximal migration of the radius. Type I is the least common dislocation but the one most likely to be associated with pain. Types II and III appear to be roughly equally prevalent. Type III is associated with the most loss of motion, usually supination. Deformity of the radial head without subluxation also has been reported. 22 Finally, Wiley and colleagues 86 have reported congenital anterior and lateral dislocations.

Other Bony Problems
Hypoplasia of the distal humerus may occur; the resulting deformity may cause ulnar neuropathy, either im-mediately, from synovial cysts, or chronically, due to abnormal elbow growth and nerve traction. 74 Congenital pseudarthrosis of the olecranon has been reported but is exceedingly rare. 66

SOFT TISSUE ANOMALIES
Soft tissue anomalies or absences may interfere with elbow function as much as bone or joint deformities. These anomalies have been subdivided into syndromes with contractures (pterygium syndromes, congenital muscular atrophy and myopathy syndromes), control deficiencies, isolated tissue anomalies (triceps absence or contracture), and congenital soft tissue tumors.

Contractures
The classic malformation with contracture is pterygium cubitale, in which almost every soft tissue is abnormal and a severe flexion contracture exists. 23, 24 The condition also has been called cutaneous webs and webbed elbow; it is but one manifestation of a congenital syndrome that may affect the neck, axilla, elbow, knee, or digits. A survey of 240 cases of cutaneous webs reported in the literature included 29 in the region of the elbow. 23 The web may be unilateral or bilateral, or symmetric or asymmetric. The condition has been reported to result from both an autosomal dominant and a recessive gene. Associated abnormalities involving almost every body system have been reported. 38, 82 Other conditions resulting in formidable contractures about the elbow include fibrodysplasia ossificans progressiva and arthrogryposis.

Control Deficiencies
Arthrogryposis and its related syndromes are also included in this group but also are discussed elsewhere (see Chapters 71 and 72 ). Both flaccid and spastic palsies affect elbow control and range of motion. Simple absences or deficiencies of tissue also affect elbow control. Hypoplasia of the elbow includes deficient growth not only of osseous structures but also of the related soft tissue control elements and cover structures. 13, 58, 81 Most characteristic is probably the extension contracture of arthrogryposis. 87

Isolated Tissue Anomalies
The skin may be deficient or missing, with absence, hypoplasia, or scarring of the underlying tissues. Nerve, vascular, and lymphatic anomalies in the region of the elbow are common. 38 The anconeus epitrochlearis occasionally is present as an anomalous muscle and may cover the ulnar nerve in the cubital tunnel area, contributing to the possibility of entrapment. Other anomalous muscles that may cause nerve entrapment problems are (1) Gantzer’s muscle, an anomalous head of the flexor pollicis longus or flexor profundus that usually originates from the medial epicondyle or the coronoid process of the ulna and occasionally is a factor in anterior interosseous nerve compression; (2) a solitary head of the supinator and other anomalies of this muscle; (3) accessory muscles of the anterolateral aspect of the elbow, including the accessory brachialis or accessory brachioradialis; (4) variations in the head, origin, or insertion of the pronator teres; (5) variations of a similar nature in the flexor carpi radialis, the flexor carpi ulnaris, and the palmaris longus 53 ; and (6) an aberrant medial head of the triceps, which may snap over the medial epicondyle and irritate the ulnar nerve. 16

Congenital Soft Tissue Tumors
Tumors of the soft tissue are rare but include a wide variety of abnormalities, ranging from overgrowth to neoplasms and from multitissue hamartomas to single tissue entities. Probably the two most common tumors in the infant are the fibromatoses and vascular tumors. If the elbow area is involved, there is usually some limitation of motion.

COMBINED BONE AND SOFT TISSUE ANOMALIES
Soft tissue anomalies may coexist with mild osseous anomalies, such as those related to the supracondyloid process. 13, 53, 80 The supracondyloid process is an anomalous bony prominence extending from the anteromedial aspect of the distal third of the humerus. Struthers 81 in 1848 described the ligament associated with this process, and since then, various anomalies have been reported in connection with it. These include a more proximal branching of the ulnar artery off the brachial artery above the bony spur, a more proximal insertion of the pronator teres on the bony process, and various relationships of the neurovascular structures with bone and ligament. The symptoms—pain, tingling, numbness, and so on—usually are neuralgic, but they may be vascular.
Many of the congenital anomalies already discussed are manifest in both osseous and soft tissues. These abnormalities may be equivalent as in the supracondyloid process syndrome just discussed, or predominantly in one tissue, as in fibromatosis. More severe changes are seen with severe pterygium cubitale and severe forms of ulnar hypoplasia and phocomelia. In pterygium cubitale, or congenital webbed elbow, a skin web extends from the upper arm across the volar elbow to the forearm. Flexion is usually possible, but extension, pronation, and supination are severely limited. The muscles and neurovascular structures are incompletely developed. The bones are hypoplastic and deformed, and the elbow joint often is dislocated or severely hypoplastic. Fibrous strands represent missing muscles or tendons. Muscle hypoplasia is present posteriorly as well as anteriorly.
Severe ulnar hypoplasia is marked by radial head dislocation, diminishing segments (ranging from small to nonexistent) of the proximal ulna, variable but seldom normal motion and stability, and muscle and neurovascular abnormalities. Conditions are more normal proximal to the elbow, but distally, more abnormalities are apparent; the ulnar forearm and hand structures are particularly dysplastic. Lorea et al 46 have proposed a classification of these findings based on a review of their own experience with 46 patients and a literature review. They propose three elbow types: type 1, normal; type 2, radiohumeral synostosis; and type 3, radial head subluxation. They further recommend subclassifying the elbows as having extension (type E) or flexion (type F) contractures. Unfortunately, they do not give the distribution of these types in their series. Phocomelia may present with similar findings, or the elbow may be even more dysplastic or absent altogether (hand, wrist, or forearm may be attached directly to the shoulder or trunk).

TREATMENT OF BONE AND JOINT DYSPLASIAS

TREATMENT OF SYNOSTOSIS
The treatment of synostosis of the elbow joint, whether radiohumeral 60 or ulnohumeral, is dictated by the position of the forearm-wrist-hand unit and the function of the wrist-hand unit. These treatments have changed little over the past few decades. If the hand is absent or nonfunctional, repositioning of a synostotic elbow is clearly less important. If the hand is functional and the elbow is in a “functional” position (i.e., somewhere near midflexion), especially if the contralateral limb is normal, no treatment is likely to be necessary. For bilateral synostoses, some consideration probably should be given to positioning one arm in relative flexion and the other in relative extension.
Frequently, only one forearm bone is well represented, and this may be bowed or deformed in some manner as well as short. In addition, there may be a rotational deformity. The forearm-wrist-hand unit may point directly posterior when the upper limb is in its usual dependent position beside the torso. Although simple rotational deformities can be corrected by osteotomy at any level, multiplane deformities should be corrected at the site of maximum deformity—that is, the humeral-forearm junction—perhaps extending the correction distally in the forearm ( Fig. 13-13 ). One such method involves a posterior approach and a multiple-segment corrective osteotomy, making one or more of the segments trapezoidal in shape and rotating it 180 degrees, if necessary, to realign the unit as desired. If only one limb is involved, this desired position is usually at maximum length, with the forearm, wrist, and hand in the midposition. Derotation should be accomplished in the direction that causes the least torsion of the neurovascular structures, commonly from an internally rotated position through a clockwise rotation to a forearm midposition. Hyperextension, if present, is corrected simply to neutral or slight flexion, and the osteotomy segments are adjusted to make the best contact in the desired position; a segment may be excised if this is needed for contouring. If both limbs are involved, enough elbow flexion angle should be included on one side to allow one of the limbs to reach the face and the head. Arthroplasty has been attempted 30, 31, 39, 57 but with indifferent results; the usual result is recurrence.

FIGURE 13-13 A, Typical congenital radiohumeral synostosis with marked curving of the radial segment. B, A “shish kabob” corrective osteotomy was carried out with temporary internal fixation. Excellent correction resulted, and there were no complications. The elbow synostosis resulted in a posterior pointing forearm, wrist, and hand.
Proximal forearm synostosis may occur with elbow synostosis, in which case the elbow is derotated as described previously. If, however, proximal radioulnar synostosis occurs in the presence of a functioning elbow joint, derotation of the forearm alone may be required. The indications for this procedure seem limited. Most patients have little functional deficit. 12 Compensatory rotation at the wrist appears to be an important factor in minimizing symptoms. 62 Although many authors have attempted and a few have claimed success for passive and even active mobilization of the forearm, 8, 15, 19, 27, 37, 55 there is no body of literature that substantiates these results in a significant number of patients who have been followed for an adequate period of time. When attempted, these procedures usually involve excision of the proximal radius, including the synostotic mass; division of the entire length of the interosseous membrane; interposition of some material between the contact areas of the radius and the ulna; and tendon transfers, such as rerouting the extensor carpi radialis longus to the volar wrist for supination and the flexor carpi radialis to the dorsal wrist for pronation. A similar procedure involving the interposition of a metallic swivel has been described by Kelikian and Doumanian, 37 but few long-term results have been reported.
A more reliable procedure is that of derotation osteotomy. 27, 76 This procedure is best outlined by Green and Mital, 24, 55 who perform the rotational osteotomy through the synostosis itself. It is indicated primarily when the forearm is fused in the extreme of either pronation or supination; forearms synostotic in neutral or close to neutral function well and often are diagnosed only later in infancy or childhood because of this fact. The synostosis is approached through a dorsal incision and is transversely osteotomized. A radioulnar (in the coronal plane) K-wire or Steinmann pin is then placed distal to the osteotomy site and is left protruding externally on both sides. A longitudinal (in the sagittal plane) pin is then placed from the olecranon across the osteotomy site, and corrective rotation is carried out as desired. Because the indication is an extreme pronated or supinated position, in most instances, 70 to 90 degrees of rotation from pronation toward supination is required. If circulatory deficits appear during or after this derotation, less rotation is accepted, although an additional amount may be carried out 10 to 15 days later. The radioulnar pin may be fixed by either a plaster cast or an external fixation apparatus. Internal fixation should not be used because alteration of forearm rotation may be necessary to diminish circulatory difficulties. Goldner and associates 21 claim that these circulatory problems may be minimized by the use of derotation in the distal forearm (radius only in younger patients; radius and ulna in older patients). Their results have yet to appear in the literature except in abstract form, but the rationale seems reasonable and the technique appropriate. They recommend cross-pin fixation in children and plate fixation in adolescents and adults.
One new and unusual problem has been reported recently, as an acute sequela of proximal radioulnar synostosis: flexion contracture. Matsuko et al 49 have reported five cases in which an acute hyperflexion episode had resulted in the sudden onset of a fixed flexion contracture in teenaged boys (in four of the five cases). In each case, the problem was treated surgically. Through a lateral approach, the anterior elbow capsule was identified. In each case, a thickened band of anterior capsule was identified, under which the hyperflexed, anteriorly displaced radial head had become trapped. A simple excision of the band resulted in complete correction in each case.

TREATMENT OF ANKYLOSIS
Ankylosis that does not involve synostosis, subluxation, or dislocation of the elbow may occur. Paralyses, muscle disease, and other soft tissue abnormalities commonly restrict motion; treatment of these abnormalities is discussed elsewhere (see Chapters 71 and 72 ). Abnormalities of joint shape and joint cartilage occur but are usually treated only by physical therapy. Rotation ankylosis due to soft tissue abnormalities occurs but has minimal effect on the elbow; its treatment requires release not only of the proximal radioulnar area but also in the forearm and wrist. 5

TREATMENT OF INSTABILITY
Treatment of infantile dislocations of the radial head, whether congenital, developmental, or traumatic, depends on the degree of hypoplasia present in the forearm and elbow area. If in doubt about the configuration of the various components of the elbow joint, an arthrogram should be performed 61 ; this study may show that there is no dislocation at all but merely a deformed elbow joint with the radiocapitellar joint displaced from the usual position (see Fig. 13-12 ). Attempts at open reduction have been made, but the result is often recurrence unless both annular ligaments and ulnar length/configuration are restored ( Fig. 13-14 ). Most authors do not advise the procedure, 4, 56, 86 although recently Sachar and Mih 71 have reported good short-term results (maintenance of reduction and improved forearm rotation) in 10 of 12 children with congenital radial head dislocation operated on between ages 7 months and 6 years. They reported that the most common finding was an interposition of the annular ligament, which they divided and then repaired in its anatomic position. Follow-up was short, however, averaging less than 2 years, with the longest being only 41 months.

FIGURE 13-14 A, Anteroposterior and lateral x-ray views of a radial head dislocation in a limb with other congenital anomalies but with a fairly normal skeleton at the elbow. Although this fulfills the requirements usually listed for congenital dislocation, the dislocation may simply be developmental, related to the unequal length of the two forearm bones. B, Postoperative lateral radiogrphs after open reduction of the dislocated radial head and internal fixation. A second operation was carried out a year later, at which time the radius was shortened and the annular ligaments were reconstructed; repeat reduction of the radial head also was performed.
The alternative to attempted reduction of congenital or infantile radial head dislocation is to accept the imposed disability (some limitation of forearm rotation, ranging from a few degrees to more than 90 degrees; occasional limitation of elbow motion; and infrequent pain) and proceed with radial head excision, if needed, at maturity. 19 - 21 ,38 ,48 ,79 As noted in a long-term follow-up study, 4 painful arthritis is typical only of the least common type I deformity. Relief of pain and cosmesis are more likely to be benefited from surgical excision; motion is seldom improved. 4

TREATMENT OF SOFT TISSUE DYSPLASIAS
Treatment of most soft tissue problems at the elbow level is discussed in other chapters. Arthrogryposis, as well as other flaccid palsies, is covered in Chapter 71 . Spastic neurogenic problems are discussed in Chapter 72 , and nerve entrapment around the elbow is discussed in Chapter 80 . Successful treatment for other soft tissue dysplasias at the elbow is rare. Aplasia cutis congenita has occurred in the elbow area. In the author’s experience, it was associated with scarring and hypoplasia of the regional forearm muscles plus reactive deformity of the underlying bones. Resurfacing with a skin and subcutaneous flap was eventually necessary, followed by tendon transfers, which in this instance were required to provide extensor function of the wrist and hand. Muscle anomalies may result in either mechanical problems (snapping or catching) 16 or neurovascular entrapment, as discussed in Chapter 80 .

TREATMENT OF COMBINED BONE AND SOFT TISSUE DYSPLASIAS
Pterygium cubitale remains an unsolved challenge. Attempts at treatment have included Z-plasty, skin grafts, and release of other tight structures. Improvement has been limited, and risks are high. 23, 24 Because there is no substantial report in the literature describing a reliable and useful method of treatment, no recommendations for surgical treatment are offered. Techniques of bone shortening to permit a greater safe excursion of the neurovascular structures or techniques of vascular and nerve grafting have been attempted, but adequate reporting is not yet available. The lengthening-stretching techniques of Ilizarov have been tried by a few investigators, so far with limited success. The hands in pterygium cubitale are often deficient also, but because limited excursion of the elbow is available in flexion, at least they are usually able to reach the upper trunk, the face, and the head.
In severe forms of ulnar dysplasia, the elbow often displays adequate range and stability. Occasionally, the displaced radial head is sufficiently limiting or symptom provoking so that treatment is offered. Although excision of the radial head and a sufficient portion of the shaft to resolve the mechanical block might suffice, the desire to stabilize and lengthen the forearm plus the fear of recurrent encroachment by the radial shaft usually lead to a recommendation for a one-bone forearm procedure ( Fig. 13-15 ). 9 This is carried out as follows:
1. Use a long lateral incision that covers the distal half of the arm, the elbow, and the proximal half of the forearm.
2. Mobilize the anterior flap, identify and protect the radial nerve, and identify and mobilize the anteriorly and radially dislocated radius.
3. Mobilize the posterior flap, identify the short ulnar fragment, and uncover the interosseous space.
4. With both bones visualized through both anterior and posterior intervals (obviously, the procedure can be performed through an anterior approach only or through both a proximal anterior and a distal posterior approach, but we have found that access and safety are preferable this way), the maximum forearm length that the soft tissue will accept is judged by manual displacement.
5. The radius then is osteotomized at the length just determined, and the proximal fragment is removed.
6. The distal fragment is aligned with the short ulnar fragment, and contact is maintained by an intramedullary pin drilled through the olecranon, along the ulnar medullary cavity, across the osteotomy site, and along the radial intramedullary space until it penetrates the radial cortex at some point. (The forearm position, usually the midportion, should be set before this distal penetration occurs.)
7. The usual support dressings (long arm splint-dressing combination initially, perhaps changed to a long arm cast later for the older child) are used until healing occurs (4 to 6 weeks). The supports are then discontinued, and the pin is removed.

FIGURE 13-15 A, A lateral view of an elbow in ulnar agenesis shows an apparent dislocation proximally and anteriorly of the radial head. Although the ulnar agenesis is congenital, the dislocation is probably developmental. Clinical findings suggested that this was a true dislocation. B, There is occasional need for excision of the dislocated radial head and combination of the proximal ulna and distal radius to form a one-bone forearm, as seen here. This changes both the appearance and the function of the elbow as well as the forearm (the range of motion of the elbow is usually improved; the forearm position becomes fixed).
In phocomelia, the elbow is seldom the site of the infrequent surgical attention given to this condition, but there may be an occasional indication for a one-bone forearm procedure or for simultaneous lengthening and stabilization at an unstable elbow segment. 77

COMPLICATIONS



Overtreatment
In many cases, the severe upper limb anomaly, particularly if it is of the sporadic variety, is associated with a completely normal contralateral upper limb. In such cases, surgical treatment may have little effect on the long-term functional level of the patient. 6 Therefore, it also is important to consider the likely practical gains from therapy before proposing an intervention. As has been noted, many synostotic forearms function well, even if in a poor position owing to compensatory hyper-rotation at the wrist. Such factors need to be considered carefully before embarking on a surgical adventure.

Unwarranted Treatment Due to Misdiagnosis
This problem, present in any medical management situation, is a particular hazard with congenital anomalies. In the infant, testing of the neurovascular supply, dynamic and static control elements, and structural and support elements is difficult and uncertain. Interpretation of radiographs, when so much of the skeletal tissue is still cartilaginous, is deceptive. Nevertheless, the best review possible is needed if surgery is contemplated. This may require examination under sedation or special radiographic techniques such as arthrography, computed tomography or magnetic resonance imaging studies, cineradiographic motion and stress studies, and others. It should be recalled that “hands-on” examination is particularly valuable in the child because much cartilage is not yet bone and much muscle and tendon can be palpated better than tested.

Infection
This is a serious problem after any surgical procedure, and the usual wound management preventive measures are employed. The ability to apply a splint dressing that will maintain the desired position and stay in place is important in infants, but must not over-ride the need for wound inspection if infection is suspected.

Vascular Compromise
Vascular damage due to direct insults, compartment pressure increase, or indirect damage from stretch or torsion does occur. The stretch-torsion injury is a particular risk in the corrective osteotomies used to treat synostosis. For this reason, circulation should be checked during the osteotomy procedure. For osteotomies in the proximal forearm or elbow, fixation that can be removed or adjusted to decrease vascular stress is necessary. The circulatory pattern in congenitally abnormal arms is almost always abnormal; if further, extensive alteration in anatomy is anticipated, preliminary angiography may be help-ful. Doppler assessment before and during surgery is invaluable.

Nerve Damage
Nerve injury due to dissection or compression at anatomic entrapment points during postoperative reaction, stretch, or torque stress also may occur. Torque stress usually can be monitored by assessing the effect of the stress on the vascular supply. The other possibilities are best controlled by adequate exposure and careful dissection. Regardless, close and skilled postoperative monitoring is essential.

Physis Damage
Partial or total destruction of the physis may result from bone cutting, pin or other fixation, or damage to the local physis circulation. Care should be taken to avoid physeal damage, particularly because most such limbs are hypoplastic and short already. A pin passing near the center of and at right angles to the physis seems to run the least risk of serious damage.

Joint Damage
Incongruous, malformed, and abnormally surfaced joints are common with congenital problems, and the investing soft tissue, motor units, and even skin also may limit normal joint function. Therefore, careful preservation of the available joint structures is important; this includes avoiding pin breakage in the elbow joint. Many surgeons, for instance, fix the ulna and radius rather than the humerus and radius to minimize the chances of intra-articular pin breakage after radial head reduction. Recurring elbow or forearm stiffness after operations for congenital elbow area anomalies is the most depressingly common complication of all. Pharmacologic suppression of scar formation and early continuous passive motion for these tiny arms may help, and both treatments should be available in the future.

CONGENITAL ELBOW REDUX
Can a topic be brought to life, or at least reinvigorated? These questions arise as the authors peruse their prior efforts and the literature since those efforts and note that little has changed. There is still uncertainty regarding the relative incidence of the two most common congenital problems at the elbow, radial head subluxation or dislocation versus proximal radio-ulnar synostosis. Treatment for radial head dislocation still runs the gamut from waiting for symptoms/disability, then removing the radial head 10 to open reduction, which may vary from removal of the annular ligament from the joint and reconstructing it in normal position to open reduction, corrective osteotomy of the ulna and reconstruction of an annular ligament, similar to the methods used for similar problems in old Monteggia injuries. 85 Usually, radioulnar synostosis continues to be treated by corrective osteotomy, although new methods have been designed with osteotomies of both the radius (distally) and the ulna (proximally) with immediate correction if the deformity is not too severe 59 or staged correction for the severe deformities. 44 The venturesome among us are still, case by case, trying synostosis excision and interposition of various substances, recently using a vascular fascio-fat graft. 34 The association of radial head subluxation or dislocation with other conditions continues to be newsworthy with new reports including congenital pseudarthrosis of the forearm 41 treated by a one-bone forearm procedure in one case 26 and treated by resection and internal fixation plus a vascularized fibular graft in another case. 68 There are many reports of radial head subluxation or dislocation with other conditions 17, 40, 73 and with paralyses. 65 It is well known that shortening of the ulna from any cause risks of subluxation or dislocation of the radial head, but the association with radial longitudinal deficiency (44% of extremities with type 1 [more than 2 mm. shortening of the radius] radial deficiency 32 ) is not as well known. However, it is certain that there is a familial component to some instances of radial head dislocation. 69
So, what has changed in the last decade in this troublesome arena? Very little, and this is also troublesome. The potential for advances is overwhelming. Stem cell manipulation, embryonic and fetal alterations, early and late childhood intervention offer different and, as yet, minimally explored options. Solutions to the unsolved problems will involve both biologic and biotechnology approaches, and probably combinations of the two. The authors believe that this niche area has been dormant long enough and anticipate a need for both national and international interactions between all interested parties. In the next edition of this text, we hope to report on a tsunami of interactive investigations.

SUMMARY
Congenital elbow dysplasia is a more common problem than is generally realized. If it is mild, elbow function is minimally affected; if it is severe, problems of the entire limb or the wrist and hand often take precedence. In the few instances, when the elbow abnormality is isolated and relatively severe, surgical assistance is available but is less than satisfying. The most common and provocative problem is that of radial head subluxation or dislocation, in which the abnormality may be due to one or more of three differing etiologies: congenital, traumatic, or developmental (resulting from congenital, traumatic, infectious, tumor, or other causes). Effective management protocols have been developed, but unsolved problems still abound.

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CHAPTER 14 Supracondylar Fractures of the Elbow in Children

Anthony A. Stans

INTRODUCTION
Supracondylar humerus fractures are the most common fracture about the elbow in children and have the highest complication rate for elbow fractures in this age group. 8, 16, 39 These compelling facts continue to pique the interest and hold the attention of orthopedists who treat pediatric patients. Since the last edition of this text, issues that have generated the most discussion regarding supracondylar fracture treatment concern timing of reduction and treatment as well as pin configuration used for fracture stabilization. Both issues are addressed in the body of this chapter.

INCIDENCE AND ETIOLOGY
Supracondylar humerus fractures almost exclusively affect the immature skeleton. 41, 50 Eliason 25 reported that 84% of supracondylar fractures occurred in patients younger than 10 years. The peak age for supracondylar humerus fracture has been reported to be between ages 6 and 7 years, and the left arm is injured more frequently than the right. * Previous reports have suggested that supracondylar fractures are common in boys, but more recent studies have documented an equal sex distribution. †
Traditional teaching has held that the peak incidence for extension-type supracondylar humerus fractures occurs at approximately age 7 because that is the age of maximum elbow flexibility and hyperextension. This mechanism has been confirmed by research suggesting that a fall on a hyperextended elbow produces a supracondylar humerus fracture, whereas a fall on an outstretched arm without elbow hyperextension is more likely to cause a distal radius fracture. 60 Hyperextension converts what would be an axial loading force to the elbow into a bending moment. The tip of the olecranon acts as a fulcrum, causing the fracture to occur through the relatively thin bone of the olecranon fossa ( Fig. 14-1 ). The distinctive shape of the humeral metaphysis with the medial and lateral condyles and columns, and the narrow midpoint of the olecranon fossa, adds to the instability of the fracture, particularly when there is rotation and tilting of the distal fragment. 62, 63

FIGURE 14-1 A, Transverse and sagittal sections of the distal humerus. The shaft diameter is large above the supracondylar foramen. B, However, if a cut is made through the supracondylar foramen, the “bicolumnar” nature of this region becomes evident, looking proximally ( C ) and distally ( D ).
(From Ogden, J.: Skeletal Injury in the Child. Philadelphia, Lea & Febiger, 1983.)
Knowledge of elbow anatomy is important to understanding the cause of the injury, and to understanding effective treatment principles (see Chapters 2 and 3 ). The stability of the elbow derives from bony and soft tissue structures. 33, 61, 66 Soft tissue stability on the lateral aspect of the elbow is provided by an expansion of the triceps, anconeus, brachioradialis, and extensor carpi radialis longus. The thickened periosteum of a young child, both medially and laterally, is an important additional stabilizer of the fracture fragment and provides a medial or lateral hinge during attempted reduction ( Fig. 14-2 ). Research by Khare et al 45 has confirmed the importance of the triceps tendon’s acting as a tension band to achieve fracture stability in the flexed elbow.

FIGURE 14-2 An experimentally produced fracture shows the medial periosteal hinge and offers a glimpse of the posterior hinge. After reduction, the soft tissues hold the fragments in place. The better the reduction, the greater the security.
(From Rang, M.: Children’s Fractures, 2nd ed. Philadelphia, J. B. Lippincott, 1983.)
Because angular deformity is a common complication of these fractures, the normal variations in pediatric anatomy should be understood. The carrying angle of the elbow joint is the angle formed by the intersection of the longitudinal axis of the arm and the forearm ( Fig. 14-3 ). The normal elbow is usually in slight valgus alignment, but this feature varies among children. 1, 17, 77 Smith 77 noted that, of 150 children aged 3 to 11, the carrying angle in boys averaged 5.4 degrees and ranged from 0 to 11 degrees, whereas in girls, it averaged 6 degrees and ranged from 0 to 12 degrees. Aebi 1 observed that the measurements were not constant and changed as the child matured, tending to decrease in magnitude and in variation between children.

FIGURE 14-3 A, Change in the carrying angle cannot be detected when the flexed elbows are examined from in front. B, Change in the carrying angle is apparent, however, when the flexed elbows are examined posteriorly. On the right, the bone prominences (black dots) can be seen to have tilted medially. C, With the arms extended, a 25-degree varus deformity of the right arm can be seen in a 9-year-old boy 2 years after a supracondylar fracture of the right arm. There is no limitation of motion. Note that the normal carrying angle of the left arm is 0 degrees. D, When the varus elbow is acutely flexed, the hand points laterally, away from the shoulder joint. This view also demonstrates the medial tilt of the bone prominences.
(From Smith, L.: Deformity following supracondylar fractures. J. Bone Joint Surg. 42A:236, 1960.)
Although not commonly associated with abuse in the past, a recent report found that 36% of patients younger than age 15 months at the time of their supracondylar fracture sustained the fracture as a result of abuse. 79 Clinicians must exclude “nonaccidental trauma” as a potential cause of injury whenever an infant presents with a supracondylar humerus fracture.

CLASSIFICATION
A classification system should guide treatment, provide information on prognosis, and facilitate research by ensuring that similar injuries are compared in the literature. The vast majority of supracondylar humerus fractures can be classified as either flexion or extension injuries, a distinction based on the radiographic appearance and the mechanism of injury. The distinction is important for treatment because the reduction maneuvers are essentially opposite for the two fracture types and flexion-type fractures are significantly more difficult to reduce by closed means. A small minority of fractures exhibit multidirectional instability and do not fit into either flexion or extension types. 49 Recognition of multidirectional instability is helpful in formulating an effective treatment strategy.

FLEXION-TYPE FRACTURES
Flexion-type fractures are the result of a direct fall onto a flexed elbow in which a powerful flexion force is applied to the distal humerus, usually through the olecranon. The distal humeral fragment is displaced anteriorly, and the fracture line crosses the humerus from the distal posterior to the proximal anterior aspect ( Fig. 14-4 ). Flexion-type fractures are frequently completely displaced and are difficult to reduce by closed means. The reduction maneuver for flexion-type fractures involves elbow extension or involves using the forearm to apply a posterior-directed force to the anteriorly displaced distal fracture fragment.

FIGURE 14-4 A, Flexion-type supracondylar fracture with anterior and medial angulation. B, Lateral view. Note also that what appears to be an avulsion of the medial epicondyle is really due to the rotation of the distal humerus and the oblique orientation of the film.

EXTENSION-TYPE FRACTURES
Extension-type fractures typically occur as the result of a fall onto an outstretched arm with a hyperextended elbow. The fracture line traverses the distal humerus from the proximal posterior to the distal anterior aspect. Displacement varies from none to marked displacement with fracture fragments separated by interposed soft tissue. Numerous classifications systems have been devised for extension-type supracondylar humerus fractures, 10, 24, 40, 41, 68 but the classification system attributed to Gartland 31 is the most commonly accepted system in use today. As described by Gartland, the classification system is simple, reproducible, helpful in guiding treatment, and provides information on prognosis and potential complications. A very similar fracture classification system was published in the German literature of the early 20th century by Felsenreich. 26

TYPE I
Type I fractures are nondisplaced ( Fig. 14-5 ). In many patients, the fracture line may not be visible on injury radiographs, but the posterior fat pad sign, palpable tenderness in the supracondylar region, and an appropriate mechanism of injury allows the physician to establish a correct diagnosis. The diagnosis is often confirmed when periosteal callus is seen on radiographs taken 3 weeks after the injury. If recognized and treated appropriately, type I fractures should never be associated with neurovascular injury or malunion.

FIGURE 14-5 A and B, Type I supracondylar fracture with an indistinct fracture line but markedly positive anterior and posterior fat pad signs. C and D, After 3 weeks of cast immobilization, fracture callus confirms the presence of a nondisplaced fracture.

TYPE II
In type II fractures, there is displacement or angulation at the fracture site, but a hinge of bone crossing the fracture keeps the fragments in continuity. The distal fragment is most often displaced posteriorly, and apex anterior angulation at the fracture site results in a hyperextension deformity ( Fig. 14-6 ). Variations of type II fractures have also been described that involve medial impaction or rotation, which can result in cubitus varus if unrecognized ( Fig. 14-7 ). Although there are reports of neurovascular injury associated with type II fractures, such injuries are rare. 69

FIGURE 14-6 A, Type II supracondylar fracture with apex anterior angulation. B, When treated with flexion of the elbow and casting, the injury shows excellent early alignment.

FIGURE 14-7 A, Schematic view of greenstick type II fracture that is causing medial trabecular-cortical compression leading to cubitus varus. This condition must be corrected with manipulation. B, Acute cubitus varus in a 5-year-old child with a type II fracture that was not corrected. C, Mild cubitus varus can be seen 2 years later.
(From Ogden, J. A.: Skeletal Injury in the Child. Philadelphia, Lea & Febiger, 1982.)

TYPE III
Type III fractures are completely displaced fractures in which there is no continuity between fracture fragments ( Fig. 14-8 ). The distal fragment is displaced posteriorly and may be displaced medially or laterally as well. There is a much higher incidence of neurovascular complications with type III fractures, and soft tissue is usually interposed between fracture fragments. The brachialis muscle is most often interposed, but the median nerve, radial nerve, or brachial artery may also be entrapped.

FIGURE 14-8 A and B, Severe type III fracture with rotation and posterior and lateral displacement with associated neurovascular compromise.

DIAGNOSIS AND RADIOGRAPHIC EVALUATION
We define a supracondylar humerus fracture to be a transverse fracture crossing the entire width of the distal humeral metaphysis without involving the distal humeral physis. The primary challenge in establishing this diagnosis is to rule out other fractures of the distal humerus that do not meet these criteria. Fractures that can sometimes be confused with supracondylar humerus fractures include lateral condyle fractures, medial condyle fractures, and transphyseal fractures. Establishing the correct diagnosis is most difficult in patients younger than 4 years, whose ossific nuclei of the distal humerus are yet unossified.
Routine anteroposterior and lateral radiographs should be taken at 90 degrees to each other whenever a supracondylar humerus fracture is suspected. If the examiner is certain of the presence of a distal humerus fracture, because of focal point tenderness, mechanism of injury, and positive posterior fat pad sign, but is unable to identify the specific fracture pattern, 45-degree oblique radiographs often provide adequate visualization to establish the definitive diagnosis. On the other hand, if what may be a pathologic abnormality could possibly be a normal variant in a partially ossified distal humerus, comparison films of the opposite elbow allow identification of normal anatomy and determination of whether or not a fracture is present. Once a fracture is identified, the radiographic fracture classification system described earlier may be applied.
The anterior and posterior fat pad signs are often helpful in diagnosing intra-articular elbow fractures such as supracondylar humerus fractures (see Chapter 15 ). Although it is very sensitive, the anterior fat pad sign is not very specific for intra-articular elbow fractures because the coronoid fossa of the humerus (occupied by the anterior fat pad) is much more shallow than the olecranon fossa (occupied by the posterior fat pad). Any insult that causes a joint effusion may cause the anterior fat pad to become visible on the lateral radiograph. A larger intra-articular fluid collection such as fracture hemarthrosis is necessary to displace the posterior fat pad enough for it to become visible on lateral radiographs; therefore, the posterior fat pad sign is much more reliable.
Additional radiographic measurements have been described to assess fracture alignment before and after reduction. The most commonly used measurement is Baumann’s angle, the intersection of a line drawn along the longitudinal axis of the humerus and a line drawn along the physis between capitellum and distal lateral humeral metaphysis. The normal angle varies in magnitude but averages approximately 72 degrees, and it should always be compared with the uninjured contralateral elbow ( Fig. 14-9 ). 88 A second useful radiographic reference line is the anterior humeral line ( Fig. 14-10 ). If the capitellar ossific nucleus is displaced posterior to the anterior humeral line, fracture reduction should be considered. Fracture reduction should restore Baumann’s angle to a measurement similar to that of the opposite elbow on the anteroposterior view, and on the lateral view, it should restore the capitellum to a position in which the central third is bisected by the anterior humeral line.

FIGURE 14-9 Baumann’s angle is the angle formed by a line perpendicular to the axis of the humerus and a line tangential to the straight epiphyseal border of the lateral part of the distal metaphysis. In the case illustrated, Baumann’s angle is 80 degrees on the fractured left side and 70 degrees on the normal right side, indicating varus angulation of 10 degrees. The same holds true for lateral tilt and valgus angulation.
(From Dodge, H. S.: Displaced supracondylar fractures of the humerus in children: treatment by dental extraction. J. Bone Joint Surg. 54A:1411, 1972.)

FIGURE 14-10 The anterior humeral line (AHL). A, A line is drawn down the anterior humeral cortex. B, A second line is drawn perpendicular to the AHL from the anterior to the posterior extent of the capitellum and is divided into thirds. In normal cases, the AHL passes through the middle third of the capitellum.
(From Rogers, L. F., Malave, S. Jr., White, H., and Tachdjian, M. O.: Plastic bowing, torus and greenstick supracondylar fractures of the humerus: radiographic clues to obscure fractures of the elbow in children. Radiology 128:146, 1978.)
For all patients with supracondylar humerus fractures, the entire extremity should be examined and radiographs obtained of all areas where associated injuries might be present. Approximately 15% of patients with supracondylar fractures have an associated fracture in the ipsilateral extremity. 86 Supracondylar fracture associated with a Montaggia lesion has also been reported. 3, 65

TREATMENT
The goal of treatment is to obtain and safely maintain anatomic fracture alignment, promote rapid healing, and return to full and unlimited function with minimal risk of complications. Injury severity determines the ease with which this goal is attained and the most appropriate method of treatment. For extension-type supracondylar fractures, Gartland’s radiographic classification system is a helpful guide to injury severity and optimal treatment.

TYPE I FRACTURES
Because type I fractures are truly nondisplaced, there is minimal swelling and no significant risk of neurovascular injury. Immediate application of an above-elbow cast with the elbow at 90 degrees of flexion (and neutral angles of pronation and supination) is safe and is all that is necessary to prevent loss of reduction and to provide pain relief. If future swelling is a concern, the cast may be bivalved, splitting all fiberglass or plaster elements down to—but not through—the cast padding. The two halves of the cast are spread apart to accommodate swelling and held together with three or four circumferential bands of tape. Five to 10 days later, the cast is simply overwrapped with fiberglass. After 3 weeks of immobilization, the cast is removed and elbow range-of-motion exercises are begun. At 6 weeks, the fracture is essentially healed and the patient may resume full activity.

TYPE II FRACTURES
Despite an intact osseous hinge, type II fractures can vary significantly in displacement and injury severity, which determines treatment choice. For fractures in which the anterior humeral line does intersect the capitellum, reduction may not be necessary and immediate cast immobilization in 90 degrees of flexion is appropriate. Closed reduction should be seriously considered for moderately displaced fractures when the anterior humeral line passes anterior to the capitellum. In a cooperative reliable patient with minimal elbow swelling, gentle closed reduction may be performed under regional anesthesia or conscious sedation in the emergency department, and the fracture should be immobilized in an above-elbow cast with enough flexion to maintain fracture reduction (see Fig. 14-6 ). If any swelling is present, close attention to the neurovascular examination is critical when immobilizing the elbow in more than 100 degrees of flexion. Fluoroscopic obser-vation can be helpful in determining the minimum degree of flexion required to safely maintain fracture reduction.
Displaced or angulated type II fractures may be associated with neurovascular injury. Neurologic and vascular examinations, performed and documented meticulously, are essential. Swelling may make it impossible or unsafe to flex the elbow enough so that the fracture reduction can be maintained. In such situations, closed reduction and percutaneous pinning is indicated to maintain fracture reduction without compromising the neurovascular integrity of the limb. Moderately or severely angulated type II fractures may also be associated with medial column impaction, lateral column impaction, or rotation. If unrecognized, any of these three variations of a type II fracture can lead to malunion and angular deformity. Medial impaction, lateral impaction, and rotation all necessitate closed reduction, which is most dependably maintained with percutaneous pinning. 19 After percutaneous pinning, a splint or bivalved cast is applied, and 5 to 10 days later, the bivalved cast is overwrapped or the splint removed and an above-elbow cast applied.

TYPE III FRACTURES
Completely displaced supracondylar humerus fractures are intrinsically unstable, typically cause severe swelling, and are frequently associated with

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